bluuebunny/crossref_metadata_2025 huggingface dataset:
8126 PTH-Independent, Calcitriol-Mediated Hypercalcemia In Renal Cell Carcinoma
Authors: Rai Gur Kiratt K , Rosairo Anne De , Madani Kulsum , Hernan Sacoto Daniel , Franco-Akel Alberto A , Belokovskaya Regina
Published: October 2024

Disclosure: G.K. Rai: None. A. De Rosairo: None. K. Madani: None. D. Sacoto: None. A.A. Franco-Akel, MD: None. R. Belokovskaya: None.

Hypercalcemia of malignancy is a known complication of advanced cancer. It occurs through various mechanisms, one of which is via 1,25-dihydroxyvitamin D (calcitriol). Calcitriol-mediated hypercalcemia accounts for approximately 1% of cases of hypercalcemia in the setting of malignancy and is usually seen in lymphomatous solid tumors. We present a gentleman with clear cell renal cell carcinoma associated with hypercalcemia with normal levels of intact parathyroid hormone (PTH), PTH-related protein (PTHrP), and 25-hydroxyvitamin D but elevated calcitriol levels. A 48 year-old-male with no significant past medical history with complaints of fatigue, hematuria, and weight loss of 38 pounds in 3 months was following urology for an elective right-sided nephrectomy. MRI of the abdomen and pelvis found a 16.1 cm renal mass with necrotic areas, causing mass effects on the liver, pancreas, and IVC. Preoperative laboratory showed hypercalcemia of 13.7 mg/dL (corrected 13.9 mg/dL) with microcytic anemia (hemoglobin 8.8 g/dL, MCV 72 fl). Workup showed low iPTH (3 pg/dL), 25-hydroxyvitamin D (16.9 ng/dL), and phosphorus level (1.7mg/dL) with elevated calcitriol (94.3 pg/dL) and a normal PTHrP. CT chest showed multiple pulmonary nodules on bilateral lobes, with the largest nodule ∼ 4.5 mm. Hypercalcemia was managed with IV fluids, calcitonin 300 units Q12 for two days, Denosumab IV infusion, prednisone 60 mg for three days, and oral ergocalciferol 50,000 units weekly. Calcium levels normalized, after which the patient underwent nephrectomy. Pathology revealed renal cell carcinoma grade G4 with mixed features of clear cell carcinoma with sarcomatoid and rhabdoid features. We report an incidental finding of hypercalcemia in a patient with renal mass. The elevated calcitriol levels can be attributed to ectopic calcitriol production through the renal mass. Post nephrectomy calcium levels remained within normal range for consecutive weeks. With this, we concur that hypercalcemia most likely originated from the renal mass that had ectopic production of calcitriol. Dysregulated calcitriol production is a well-known complication of lymphomas and granulomatous disease but is seldom reported with solid tumors. Usually, the etiology for hypercalcemia in patients with renal cell carcinoma is the overproduction of PTHrP, which was not the case with our patient. The ultimate resolution of hypercalcemia of malignancy was attained by treating the underlying malignancy.

Presentation: 6/1/2024
8743 Regulation Of Tryptophan 2,3-Dioxygenase 2 And Androgen Receptor In Triple-Negative Breast Cancer
Authors: Kuo Li-Wei , Lacey Kimaya , Spoelstra Nicole , Richer Jennifer K
Published: October 2024

Disclosure: L. Kuo: None. K. Lacey: None. N. Spoelstra: None. J.K. Richer: None.

Background: Triple Negative Breast Cancer (TNBC) is an aggressive subtype with a peak recurrence rate within 3-5 years after initial diagnosis. Androgen receptor (AR) and Tryptophan 2,3-dioxygenase 2 (TDO2) are elevated in TNBC cells grown under anchorage-independent conditions and facilitate anoikis resistance. Several studies reported that the luminal AR subset of TNBC showed a positive enrichment of the tryptophan (TRP) catabolism pathway gene signature. Recent studies have demonstrated that aryl hydrocarbon receptor (AhR) inhibition decreases AR promoter transcriptional activity in prostate cancer. We have observed that TNBC with high AR have high levels of genes/proteins in the tryptophan catabolism pathway including the rate limiting enzyme TDO2. Hypothesis: TDO2 activity regulates AR expression through the downstream tryptophan catabolite kynurenine (KYN), which binds and activates AhR and AhR and AR may work together to promote TNBC progression. Methods: Human TNBC cell lines: MDA-MB-453, BT549, SUM159PT ​ were used in this study and the expression of TDO2 and AR were examined by immunohistochemistry (IHC) and western blot. TDO2 was stably knocked down (KD) via shRNA or overexpressed (OE) using lentivirus transduction. Mass spectrometry-based metabolomics were used to measure changes in TRP catabolite levels, and a cytokine array (R&D) was utilized to analyze conditioned media. Results: TDO2 and AR protein are positively correlated in human TNBC cell lines. Although overexpression of TDO2 did not alter AR protein expression in SUM159PT, in the human MDA-MB-453, which have high levels of AR, knockdown of TDO2 (shTDO2) reduced AR protein by 40% and production of kynurenine (KYN) was reduced by 50% (p<0.0001). This suggests that TDO2 activity, specifically KYN binding to AhR, may influence AR protein levels. Conditioned media (CM) from TDO2 OE and KD respectively increased and decreased CXCL5 and IGFBP2. Lastly, TCGA database analysis of TNBC tumors with high levels of both AhR and AR showed significantly shorter patient survival (HR=1.47, log rank p=0.046) compared to those with tumors with lower amounts of both genes. Conclusion: TDO2 and AR are positively correlated in human TNBC cell lines. Tumors with high levels of both AR and AhR result in significantly shorter survival time for TNBC patients. Knockdown of TDO2 significantly reduced KYN production and AR expression in luminal AR TNBC cell lines and future experiments will focus on the underlying mechanism behind this and whether it is dependent on KYN-mediated activation of AhR and if AhR stabilizes AR in TNBC.

Presentation: 6/3/2024
6477 Surprise Finding For A Thyroid Nodule: Metastatic Renal Cell Carcinoma
Authors: Xu Adele , Hsu Emory
Published: October 2024

Disclosure: A. Xu: None. E. Hsu: None.

Introduction: A patient with an incidental and asymptomatic thyroid nodule underwent fine needle aspiration biopsy (FNA) after the nodule increased in size. Without a definite pathology after three FNA attempts, thyroidectomy was performed, where pathology found metastatic renal cell carcinoma (RCC). Clinical Case: A 64 year old woman had a past medical history of obesity, type 2 diabetes, RCC (stage I: pT1bN0M0) treated with right radical nephrectomy five years prior and thought to be in remission, remote smoking history smoking, and coronary artery disease with coronary artery bypass graft (CABG) two months prior, on anticoagulation. The patient reported a distant history of right thyroid lobectomy over a decade prior for unclear reasons, but she was adamant that the pathology was benign. Two years prior to presentation, CT chest done for RCC surveillance had detected a left thyroid nodule. Ultrasound at the time revealed a 3.6 x 1.9 x 2.3 cm solid, isoechoic nodule in the upper left lobe, which was not taller than wide, and had smooth margins and no echogenic foci. A repeat ultrasound at the time of presentation showed interval growth of the nodule, now measuring 4.3 x 2.1 x 2.9 cm. FNA was unsatisfactory, yielding predominantly blood. Patient felt well and had no compressive neck symptoms. We opted to wait two months and repeat FNA, which resulted as atypia of undetermined significance - Bethesda category III (AUS). We recommended completion thyroidectomy, but patient preferred to avoid surgery. We decided to wait two months and repeat FNA with molecular testing. This third FNA resulted AUS again; however, due to non-medical reasons, molecular testing was not performed. Another ultrasound showed slight growth of the nodule, 5.1 x 2.9 x 2.0 cm, which appeared hypoechoic now, but was still not taller than wide, with smooth margins and no echogenic foci. Completion thyroidectomy was performed, with pathology showing metastatic clear cell renal cell carcinoma. Immunostains were positive for carbonic anhydrase and renal cell carcinoma marker and negative for TTF-1. Whole-body PET-CT showed no hypermetabolic foci, and a repeat PET-CT one year later still showed no evidence of metastatic disease. Other than a hospitalization for COVID-19, patient is doing well and asymptomatic now over a year after her thyroidectomy. Oncology will continue routine surveillance imaging for her metastatic renal cell carcinoma thought to be in remission. Clinical Lessons: This case of metastatic renal cell carcinoma to the thyroid adds to the small body of literature showing the thyroid as a possible site of RCC metastasis. The long time interval between initial RCC presentation and metastasis to the thyroid makes this diagnosis more difficult; however, clinicians should be aware of the possibility, making thyroidectomy a stronger option in cases where FNA cytology is indeterminate.

Presentation: 6/2/2024
7510 Use of Tumor Markers and Surgery in the Management of Medullary Thyroid Cancer During Pregnancy
Authors: Garver Megan , Lisa Vaz Cherie
Published: October 2024

Disclosure: M. Garver: None. C. Vaz: None.

Introduction: Thyroid cancer is the second most diagnosed cancer during pregnancy, predominantly differentiated thyroid malignancies. [1] MTC during pregnancy is rare and challenging to manage due to its aggressive nature. We describe the successful diagnosis and management of MTC during pregnancy. Clinical Case: A 28 yo woman presented with a rapidly growing neck lump for 2 months with an associated unintentional 10lb weight loss and without compressive symptoms. She had no history of childhood radiation exposure or family history of thyroid cancer. Physical exam revealed a hard L lobe thyroid nodule without palpable lymphadenopathy. The patient was 5 weeks pregnant at the time. A neck US revealed a 4.2x2.7x2.0 cm L solid isoechoic thyroid nodule with punctate echogenic foci and microcalcifications. The nodule was classified as TIRADS 4 and ATA high suspicion. FNA noted Bethesda IV with positive IHC stains for chromogranin and calcitonin. Afirma MTC classifier was positive, confirming diagnosis of MTC. At 7 weeks gestation, calcitonin was markedly elevated at 3508 pg/mL (n <5 pg/mL), CEA 29.5 ng/mL (n <2.5 ng/mL) and calcium 10.3mg/dL (8.6-10.2mg/dL). Plasma normetanephrines were elevated to176 pg/mL (n <148 pg/mL) with normal metanephrines 28 pg/mL (n <57 pg/mL) and normal 24-hour urine metanephrines. CT neck revealed 3.2x2.8cm L thyroid nodule without cervical lymphadenopathy. Due to pregnancy status, additional imaging to assess for metastatic disease was deferred until after delivery. Genetic testing did not identify mutations within the thyroid cancer panel including APC, CHEK2, DICER1, MEN1, PRKAR1A, PTEN, RET, SDHB, SDHD, and TP53. The patient underwent total thyroidectomy with neck dissection at 19 weeks gestation without complication. Two weeks postoperative Calcitonin was 2 pg/mL(n <5 pg/mL) and CEA was undetectable. Conclusions: The effect of pregnancy on MTC is not well studied because of low incidence. Guidelines on the timing of surgery for MTC diagnosed during pregnancy are lacking. While evidence confirms that surgery can be safely postponed until after delivery for low risk differentiated thyroid malignancies, there is no consensus on timing of surgery for MTC. Given the aggressive nature of MTC, along with marked elevation of calcitonin and CEA in this case, surgery was performed in the 2nd trimester with excellent outcome. Data is conflicting on accuracy of calcitonin and CEA during pregnancy, with some reports suggesting falsely high levels due to pregnancy. The sharp decline in calcitonin and CEA 2 weeks postoperatively suggested these were truly elevated due to MTC and unaffected by pregnant status. We suggest that calcitonin and CEA be followed similar to non-pregnant cases with MTC. Resources: 1.Khaled, H. M., Lahloubi, N. A., & Rashad, N. (2016). A review on thyroid cancer during pregnancy: Multitasking is required. Journal of Advanced Research, 7(4), 565–570.

Presentation: 6/2/2024
12572 Incidental Adrenal Enlargement On Ct Scan In South Brooklyn Health, How Often Is It Functional?
Authors: Ruggiero R , Simon N
Published: October 2024

Disclosure: R. Ruggiero: None. N. Simon: None.

Background: Incidental findings of adrenal hyperplasia are increased due to the widespread rise in cross sectional imaging, as well as improvement of imaging modalities. There is a lack of literature reporting on the prevalence of incidental adrenal hyperplasia. One study reported a prevalence of 11.3%. Adrenocortical hyperplasia can result from endocrine disorders such as ACTH dependent and independent Cushing syndrome, primary aldosteronism, Multiple Endocrine Neoplasia type 1, and congenital adrenal hyperplasia. Other reported causes are radiographic adrenal enlargement of unknown cause and without clinical or biochemical manifestations, inflammation, neoplasms, and depression. Most cases are a radiographic finding with no clinical significance. One study reported that 69.23% of cases were nonfunctional. There are currently no guidelines in place for biochemical evaluation of incidental adrenocortical hyperplasia. Patients are typically referred to endocrinology services. Objective: The purposes of this study was to: 1. Evaluate the number of patients referred to endocrinology clinic for incidental abnormal adrenal imaging. 2. Examine the percentage of abnormal adrenal imaging findings on CT scan, in particular adrenal hyperplasia, that are hormonally active. Methods: This was a retrospective study of patients who were referred to endocrinology clinic or electronic endocrine consult for incidental abnormal adrenal imaging, excluding those with clear diagnosis of masses, nodules, adenomas, or cysts. Data collected included demographics, type of study imaging and radiologist reader, hormonal studies, comorbid conditions such as diabetes mellitus, hypertension, obesity, osteoporosis, as well as visit type to endocrinology service (e-consult vs in person). Results: The total number of consults referred to endocrinology during this period was 138. Due to repeat referral or having an adrenal pathology other than hyperplasia, 83 patients were excluded from analysis. There were 55 patients with isolated adrenal hyperplasia, 86% of whom were Caucasian, 11% Hispanic, and 78% of patients were female. Median age 63 years old. Hypertension was noted in 69% of patients, 36% had diabetes mellitus or dysglycemia, 36% were obese, and 1.8% had osteoporosis. Imaging reading was performed by 3 radiologists, 75% of cases reported by one reader. Only 5% of referrals were answered as an e-consult. About 27% of patients did not show up to establish care. Hormonal workup was completed by 60% of the patients, with 16 % having abnormal findings. One patient required confirmatory workup. No patients required treatment. Conclusion: Adrenal Hyperplasia is often an incidental radiologic finding, that can be reader dependent. Most cases are nonfunctioning without abnormal findings on hormonal workup. E-Consultation can be an efficient tool to help PCP and reduce endocrine clinic visits.

Presentation: 6/1/2024
7191 When Pain Is Misdiagnosed: A Case of Parathyroid Carcinoma Masked as Fibromyalgia
Authors: Pham Huynh , Kumar Pratima V , Taylor Steven
Published: October 2024

Disclosure: H. Pham: None. P.V. Kumar: None. S. Taylor: None.

Parathyroid carcinoma is a rare and aggressive cause of hyperparathyroidism, typically associated with <1% of primary hyperparathyroidism cases. Incidence occurs mainly in the 5th decade of life, with less than 4% of all cases presenting in patients under age 30. Here, we highlight a case involving a 28-year-old woman with fibromyalgia who presented for worsening right shoulder pain in the setting of progressive, poorly characterized pain for the past year. Her initial physical exam was unremarkable aside from a non-tender left sided neck enlargement. However, her laboratory results were significant for corrected serum calcium of 15 mg/dL, serum phosphorus of 2.3 mg/dL, parathyroid hormone (PTH) >2500 pg/mL, and alkaline phosphatase 1604 units/L. X-ray of her right shoulder demonstrated mottled bone concerning for degenerative disease. Thyroid ultrasound revealed a complex cystic lesion posterior to the left thyroid lobe measuring 5.3 x 3.9 x 2.9 cm, worrisome for giant parathyroid adenoma. CT abdomen/pelvis showed diffuse osteosclerosis and innumerable lytic lesions, consistent with osteitis fibrosa cystica, as well as bilateral nephrolithiasis, likely medullary nephrocalcinosis. Her hypercalcemia was treated with aggressive hydration with normal saline and IV pamidronate. She underwent surgical resection of her parathyroid adenoma, which was unfortunately complicated by symptomatic hypocalcemia requiring prolonged care in the ICU. Her calcium levels did improve within a few days, and she was subsequently discharged with close outpatient follow-up. Final pathology report showed predominant thickened trabecular growth pattern with focal vascular invasion consistent with parathyroid carcinoma. Our patient’s case represents a rare presentation of parathyroid carcinoma in a young patient without any additional risk factors. Although atypical, her severe symptomatic hypercalcemia, nephrolithiasis, presence of large neck mass, and diffuse skeletal disease warranted immediate concern for malignant hyperparathyroidism instead of benign adenoma. Delayed diagnosis in our patient led to prolonged bone disease and severe complications. While hungry bone syndrome typically manifests post-parathyroidectomy in patients with end-stage renal disease, our patient experienced this complication in the setting of advanced, untreated hyperparathyroidism. We should consider hypercalcemia and hyperparathyroidism in our differential diagnosis for chronic pain, especially if pain remains uncontrolled with conservative measures. The most appropriate initial test for evaluation of hypercalcemia is a PTH level to distinguish between PTH-dependent and PTH-independent etiologies. Parathyroid carcinoma, even in young patients, should be considered when PTH is >3x upper limit of normal, serum calcium is >14, or skeletal and renal involvement is present.

Presentation: 6/3/2024
6564 A Case of Severe Hypercalcemia in Carney's Complex
Authors: Chippior Jessica , Rayan Melanie , Wright Laura , Steven Kirschner Lawrence , Wai Ing Steven
Published: October 2024

Disclosure: J. Chippior: None. M. Rayan: None. L. Wright: None. L.S. Kirschner: Grant Recipient; Self; Medpace, Sparrow, Corcept Therapeutics, Corcept, Spruce, CinCor, Crinetics, Adrenas. S.W. Ing: Grant Recipient; Self; Alexion Pharmaceuticals, Inc., Amgen Inc, Radius Health, Inc, Takeda, Ultragenyx, Amolyt, Bridge Bio.

Carney complex is a rare syndrome with fewer than 750 reported cases, characterized by lentigniosis, myxomas, and the occurrence of both endocrine and non-endocrine tumors. An inactivating mutation PRKAR1A, which encodes for the type 1A regulatory subunit of Protein kinase A, is responsible for over 70% of familial cases and 37% of sporadic cases. A 31-year-old female with a history of Carney complex, Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD), facial lentigines, spinal Schwannomas, and recent ischemic stroke secondary to embolization of a cardiac atrial myxoma, was transferred to our medical center for hyperemesis and severe hypercalcemia. Albumin-corrected serum calcium measured 15.4 mg/dL (8.6-10.5 mg/dL), ionized calcium 7.8 mg/dL (4.6-5.3 mg/dL) associated with suppressed PTH, normal PTH-related protein, and elevated bone turnover markers, C-telopeptide 4,273 pg/ml (150-635) and Procollagen Type 1 N-terminal Propeptide 222 mcg/L (19-83). Evaluation for etiology of hypercalcemia revealed elevated 1,25 dihydroxy vitamin D at 107.0 pg/ml (20-79) and elevated interleukin-6 at 11 pg/ml (<6.4). IL-6 is expressed by cardiac myxomas. Serum angiotensin-converting enzyme level was 50 U/L (16-85) and infectious workup was negative for potential granulomatous causes of elevated calcitriol (including testing for tuberculosis, histoplasma, blastomyces, bartonella, and coccidioides). CT angiogram of the abdomen and pelvis (completed in preparation of atrial myxoma resection) revealed ground-glass opacities in bilateral posterior lung fields and multiple pulmonary nodules, with the largest measuring 8 mm. After treatment with aggressive intravenous fluid resuscitation, intramuscular calcitonin, and intravenous zoledronic acid, corrected calcium normalized to 9.4 mg/dL at discharge. Urinary cortisol was 6.2 mcg per 24-hr (3.5-45), for which she started hydrocortisone 20 mg daily to treat suspected adrenal insufficiency as excess cortisol secretion in PPNAD may be episodic. Thus remission of hypercortisolism may have unmasked an underlying hypercalcemia, and adrenal insufficiency itself may have contributed to this finding. She had excision of left atrial myxoma and has continued to exhibit normal calcium levels on steroid replacement therapy. Repeat chest CT to further characterize these pulmonary findings is planned. This case illustrates a unique constellation of endocrine features associated with severe hypercalcemia in Carney complex.

Presentation: 6/1/2024
7274 Assessing the interactome of hexose-6-phosphate dehydrogenase in breast cancer cells and identifying anterior gradient protein 2 as interacting partner by using a BioID method
Authors: Sakalauskaite Gabriele , Weingartner Michael , Bock Thomas , Birk Julia , Tsachaki Maria , Odermatt Alex
Published: October 2024

Disclosure: G. Sakalauskaite: None. M. Weingartner: None. T. Bock: None. J. Birk: None. M. Tsachaki: None. A. Odermatt: None.

Hexose-6-phosphate dehydrogenase (H6PD) catalyzes the first two steps of the pentose-phosphate pathway in the endoplasmic reticulum (ER). It is so far the only enzyme shown to generate NADPH in the ER. H6PD is involved in physiological processes such as glucose and steroid metabolism, redox regulation, and response to ER-stress. So far, only one H6PD interacting partner, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), has been reported. This enzyme uses NADPH for its well-reported role in glucocorticoid activation. However, H6PD has 11β-HSD1-independent functions, such as the recently described modulation of breast cancer cell properties. Here, we adapted the BioID approach to identify novel H6PD interacting partners in the ER. First, we generated a triple negative breast cancer cell line MDA-MB 231 stably expressing a H6PD-biotin ligase fusion protein. Then, we validated the method to confirm the known interaction between H6PD and 11β-HSD1. Next, we analyzed enriched biotinylated proteins by mass spectrometry and further assessed potential candidates by co-immunoprecipitation and functional assays. The resulting interactome revealed a potential hit cluster of protein disulfide isomerase (PDI) family members, different ER-resident chaperones and luminal calcium binding proteins. Due to its association with breast cancer, we further examined the PDI Anterior gradient protein 2 (AGR2) as H6PD interacting partner. Physical interaction between AGR2 and H6PD was confirmed by co-immunoprecipitation assay in MCF7 cells. Downregulation of AGR2 by siRNA resulted in elevated H6PD protein levels but decreased activity. Furthermore, increased H6PD activity was observed when this protein was co-expressed with AGR2 in HEK-293 cells. In conclusion, the results validated the use of the BioID approach to identify protein interactions within the ER and they revealed that AGR2 physically interacts with H6PD, thereby controlling its expression and enzyme activity.

Presentation: 6/3/2024
12347 Cholesterol Biosynthesis Inhibitor Ro 48-8071 Suppresses Growth Of Triple-negative Breast Cancer Cells By Inducing Apoptosis And Suppressing Angiogenesis
Authors: Liang Y , Hyder S M
Published: October 2024

Disclosure: Y. Liang: None. S.M. Hyder: None.

Triple-negative breast cancers (TNBC) lack ER, PR and Her2neu, proteins that are commonly targeted in breast cancer therapies. Women who suffer from TNBC have limited treatment options and are administered toxic chemotherapeutic agents. They have poor prognosis due to the emergence of drug-resistant cells that lead to tumor metastasis. New non-toxic therapeutic strategies to control TNBC progression, and prevent metastasis are urgently needed. Cholesterol is an essential structural and functional component of cell membranes necessary for tumor growth and progression. Therefore, inhibiting cholesterol production is an attractive therapeutic strategy since tumor cells grow rapidly, and need a greater supply of cholesterol. We targeted oxidosqualene cyclase (OSC), an enzyme that occurs downstream of HMGCoA-reductase in the cholesterol biosynthetic pathway, to disrupt tumor growth. RO 48-8071 (4′-[6-(allylmethylamino)hexyloxy]-4-bromo-2′-fluorobenzophenone fumarate) (RO), has emerged as a useful chemotherapeutic agent for treating several forms of primary tumors but its effect on TNBC is not known. Pharmacological doses of RO potently reduced the viability of both MDA-MB-231 and BT20 TNBC cells in a dose dependent manner (1-50 μM). IC50 values for loss of cell viability was approximately 10 μM for both cell lines following 48 h exposure to RO. Doses close to the IC50 for OSC (1-10 nM) also reduced cell viability following exposure of TNBC cells to RO for a week. Importantly, RO had no effect on the viability of normal human mammary cells. FACS analysis revealed that RO dose-dependently induced apoptosis of TNBC cell lines in vitro. In vivo, administration of 5-10 mg/kg RO to mice with BT-20 TNBC cell-derived xenografts (100 mm[3]) inhibited tumor growth with no apparent toxicity. Immunohistochemical analysis of tumor tissues at the end of treatment showed that RO increased TUNEL expression, suggesting that the in vivo effects of RO were also exerted through mechanisms affecting apoptosis. Furthermore, IHC of tumor sections showed that RO also reduced levels of the angiogenic markers VEGF and CD-31 (blood vessels) in vivo, indicating that suppression of angiogenesis is also part of the mechanism through which RO exerts its anti-tumor effects. We conclude that RO is a potent inhibitor of TNBC and that its anti-tumor effects involve mechanisms that induce apoptosis and suppress angiogenesis.

Presentation: 6/2/2024
7111 Intrapericardial Paraganglioma, An Exceedingly Rare Finding
Authors: Habibi Roshanak , Pendergrass Merri , Neda Ebrahimi , Cardenas Lara Ramiro
Published: October 2024

Disclosure: R. Habibi: None. M. Pendergrass: None. E. Neda: None. R. Cardenas Lara: None.

Introduction: Hereditary paraganglioma/pheochromocytoma (PGL/PCC) syndromes are rare tumors occasionally resulting from germline pathogenic variant in succinate dehydrogenase subunit B and D (SDHB and SDHD) genes. Hereditary forms are usually present in the posterior mediastinum. Few cases of PGL/PCC syndromes are reported in intrapericardial space. Below, we report on such a patient, illustrating the importance of genetic testing and whole-body imaging surveillance in patients with tumors suggestive of paragangliomas. Presentation: We present a case of a 25-year-old female with an intracardiac mass suspicious for intrapericardial paraganglioma. She was initially diagnosed with a large jugular when she presented to the emergency department with nausea, vomiting, headaches, with recent diagnosis of cranial nerve VI palsy and vertigo. MRI brain with and without contrast showed a hypervascular glomus jugular tumor in the right skull base with extension into the carotid space of the neck, with leftward effacement of the posterior oropharynx and flow into the right sigmoid and transverse sinus during the arterial phase, suggestive of a paraganglioma. The paraganglioma was deemed non secretory with unremarkable initial endocrine work up. Her 24 hours urine 3-methoxythyramine and dopamine levels were elevated as expected with paraganglioma. She was referred to a geneticist and diagnosed with hereditary PGL/PCC syndrome. This was secondary to a germline pathogenic variant in SDHB gene (deletion exon 8). Cardiac MRI revealed an intensely enhancing intrapericardial lesion along the anterior/superior aspect of the left atrium. Imaging features were suggestive of an intrapericardial paraganglioma, given the genetic analysis and concurrent imaging findings of neck glomus tumor. She also had abdominal and pelvic CT scan with IV contrast which did not reveal any mass. Cardiothoracic surgeon decided on non-surgical intervention. The neurosurgery team recommended surgery since surgery in the jugular foramen seemed morbid with probable multiple cranial nerve injuries. The patient eventually received courses of radiation treatment to the glomus paraganglioma of the brain which improved the size of tumor. Discussion: Paragangliomas are chromaffin tumors that arise from either sympathetic or parasympathetic ganglia. The literature reveals about 2 % or less of paragangliomas affect the chest. Most of these tumors will be found in the posterior mediastinum. The very small proportion of them found in the heart are commonly seen arising from the roof of the left atrium in addition to affecting cardiac structures. Due to a high level of vascularization and the inherent risk of hemorrhage, tissue biopsy is not typically advised. In nonfunctional paragangliomas, surgery is often the ultimate treatment.

Presentation: 6/2/2024
8072 Crosstalk between E-cadherin loss and Estrogen receptor drives tumorigenesis in Invasive Lobular Carcinoma
Authors: Ufondu Chinasa A , Musick Maggie , Joseph Sikora Matthew , Hanson Ostrander Julie
Published: October 2024

Disclosure: C.A. Ufondu: None. M. Musick: None. M.J. Sikora: None. J.H. Ostrander: None.

Estrogen receptor (ER) expression and E-cadherin (CDH1) loss are the two major molecular hallmarks of invasive lobular carcinoma (ILC) of the breast; however, it is unclear how ER signaling and E-cadherin loss crosstalk during ILC tumor formation. Furthermore, the risk of ILC is increased by estrogen-only hormone replacement treatment, but not that of the more frequent invasive ductal carcinoma (IDC), suggesting that ER may have a unique role in the initiation and progression of ILC. We hypothesize that E-cadherin loss accelerates estrogen-driven tumorigenesis by reprogramming ER DNA binding through the dysregulation of pathways and transcription factors linked to E-cadherin. To test the effect of E-cadherin loss during estrogen driven tumorigenesis, we established a CRISPR/Cas9 approach for knocking out CDH1 in primary human mammary epithelial cells (HMECs). Since primary HMECs did not show robust ER expression, we also re-expressed ER using lentiviral transduction of ESR1 into HMECs. We performed RNAseq from two independent CDH1 targeting gRNAs vs non-targeting gRNA (NTG) control (-/+ ER). Importantly, when comparing the two independent CDH1 gRNAs to NTG there were 2882 shared genes (1436 upregulated only, 1407 downregulated only) that were differentially regulated. Analysis of these shared genes showed the enrichment of estrogen response, PI3K signaling and cell cycle pathways in the CDH1 knockout cells vs control. We also observed the repression of epithelial mesenchymal transition, hypoxia-related genes and p53 in the CDH1 knockout samples vs control. Overall, analysis of the RNAseq data suggests that the loss of E-cadherin in HMECS impacts proliferation and EMT, which will be explored in future studies. In addition, we hope to identify mediators that drive estrogen-induced tumorigenesis using the mouse mammary intraductal (MIND) model, which better recapitulates the progression of ILC and response to estrogen in vivo. We injected control and CDH1 knockout cells into the mammary glands of adult female NSG mice, with estrogen supplemented in their drinking water, and assessed for engraftment using bioluminescence imaging (BLI). BLI suggests enhanced engraftment of CDH1 knockout cells compared to CDH1 wild-type HMECs and a survival advantage for HMECs expressing ESR1. Importantly, analysis of mammary glands two-month post-MIND injections showed engraftment of human cells positive for cytokeratin-5 and lamin a/c. Ongoing studies aim to assess the estrogen response in the CDH1-knockout versus control HMECs in vitro and in vivo to determine whether loss of E-cadherin contributes to ILC-specific ER activity. Understanding the unique interactions between E-cadherin loss and ER in ILC could lead to novel therapeutic approaches for the prevention and treatment of ILC.

Presentation: 6/2/2024
7401 Development and Evaluation of Ruthenium-based Photoactivated Chemotherapeutic Agents
Authors: Wilson Auden , Cejudo Briseily , Enkhbold Khuslen , Chung Yuna , Chiaino Samantha , Norris Michael R , Pollock Julie
Published: October 2024

Disclosure: A. Wilson: None. B. Cejudo: None. K. Enkhbold: None. Y. Chung: None. S. Chiaino: None. M.R. Norris: None. J. Pollock: None.

Photoactivated Chemotherapy (PACT) represents an opportunity to limit the off-target toxicity inherent to traditional chemotherapies. Selective activation of toxic effects would allow effective chemical treatment of solid tumors without the normally associated side effects. Expanding on previous work in our lab (1), we have evaluated the potential of ruthenium-based compounds as PACT agents by testing light activation, cell viability in breast cancer and lung cancer cells, biocompatibility, and DNA interactions. We have observed that active ruthenium-complexes with increased lipophilicity tend to be more toxic to the cancer cells. In addition, we have ligated known anticancer compounds (2) to our ruthenium cages, evaluated the capacity to mask the general cytotoxic effects, and examined the release of a fully active drug after light exposure. We can successfully release the active drugs with light, but when using light at 450 nm it takes about six hours of direct exposure in a cuvette to see successful conversion. We are currently systematically exploring different wavelengths of light to reduce activation time and increase potential clinical utility (3). Once optimal wavelengths are determined, cancer cell viability experiments will be performed in the absence and presence of light in order to evaluate the therapeutic window for these ruthenium-complexes. References: (1) Paul, L. et. al. J. Inorg. Biochem.2022, 235: 111930. (2) Peerzada, M. N. et. al. Eur. J. Med. Chem.2018, 155: 13-23. (3) Dunkel, P. & Ilaš, J. T. Cancers2021, 13: 40-42.

Presentation: 6/2/2024
5110 Development of Exosome-mediated Suicide Gene Therapy for Enhanced Cancer Treatment
Authors: Ku Joy , Flojo Renech , Zhang Pengyan , Lu Biao
Published: October 2024

Disclosure: J. Ku: None. R. Flojo: None. P. Zhang: None. B. Lu: None.

Existing suicide gene therapy strategies are designed to express prodrug-converting enzymes in the cytosol of cancer cells, limiting their therapeutic reach to gene-transfected cells and their immediate neighbors through bystander effects (1). This study proposes a novel approach to enhance cancer treatment by redirecting prodrug-converting enzymes into extracellular vesicles, also known as exosomes, potentially enabling metastatic cancer cells to receive therapeutic drugs through cancer-homing mechanisms (2, 3). To achieve this, we aimed to develop an exosome-based suicide gene therapy strategy employing human herpes simplex virus-thymidine kinase (HSV-TK) and cytosine deaminase-uracil phosphoribosyl transferase (CD-UPRT) enzymes. We designed and constructed two lentiviral vectors expressing chimeric fusion proteins, incorporating exosome-targeting motifs, green fluorescent protein, Gaussia luciferase, and HSV-TK/CD-UPRT. We demonstrated that both chimeric fusion proteins were properly shunted into the exosome pathways by transfection of cultured 293T and HepG2 cells, followed by real-time monitoring and confocal imaging. This was further corroborated by colocalizing these fusion proteins with well-established exosome markers, such as CD9, CD63, CD81, and XPACK. Furthermore, the isolation and characterization of secreted exosomes confirmed the successful loading of engineered enzymes onto exosomes, which were subsequently released into the conditioned media of both cell models. Importantly, initial experiments involving transfection and prodrug treatment showed that HepG2 cells were significantly inhibited (up to 84%) in a dose- and time-dependent manner when treated with the prodrug Ganciclovir in the HSV-TK model. Our study demonstrates the potential adaptation of prodrug therapy to an exosome-based platform, opening the door to a novel nano-treatment approach for cancer. Reference: (1) Thoidingjam et al., Translational Medicine communications. 2023. 8:11. (2) Lu et al., Advanced Drug Delivery Reviews. 2022. 114465. (3) Zhang et al., Signal Trnsductio and Targeted Therapy. 2023. 8:124.

Presentation: 6/2/2024
9308 GPNMB Promotes Tumor Growth and is a Biomarker for Lymphangioleiomyomatosis (LAM)
Authors: Gibbons Erin , Taya Manisha , Wu Huixing , Lopa Samia , Moss Joel , Henske Elizabeth P , McCormack Francis X , Hammes Stephen R
Published: October 2024

Disclosure: E. Gibbons: None. M. Taya: None. H. Wu: None. S. Lopa: None. J. Moss: None. E.P. Henske: None. F.X. McCormack: None. S.R. Hammes: None.

Lymphangioleiomyomatosis (LAM) is a rare, progressive cystic lung disease affecting almost exclusively female-sexed individuals. The cysts represent regions of lung destruction caused by smooth muscle tumors containing mutations in one of the two tuberous sclerosis (TSC) genes. mTORC1 inhibition slows but does not stop LAM advancement. Furthermore, monitoring disease progression is hindered by insufficient biomarkers. Therefore, new treatment options and biomarkers are needed. LAM cells express melanocytic markers, including Glycoprotein Non-Metastatic Melanoma Protein B (GPNMB). The function of GPNMB in LAM is currently unknown; however, GPNMB’s unique cell surface expression on tumor versus benign cells makes GPNMB a potential therapeutic target, and persistent release of its extracellular ectodomain suggests potential as a serum biomarker. Here we establish that GPNMB regulates TSC2-null tumor cell invasion as well as TSC2-null xenograft tumor growth, and that GPNMB expression is dependent on mTORC1 signaling. Further, we show that GPNMB’s ectodomain is released from the cell surface of TSC2-null cells by ADAM10 and 17 proteases, and we identify the protease target sequence on GPNMB. In fact, mutating this cleavage sequence so that the GPNMB ectodomain can no longer be shed results in cessation of TSC2-null tumor growth. Finally, we demonstrate that GPNMB’s ectodomain is present at higher levels in LAM patient serum compared to healthy controls, and that ectodomain levels decrease with mTORC1 inhibition, making it a potential LAM biomarker.

Presentation: 6/3/2024
8770 Highly Multiplexed Mapping of the Ductal Carcinoma In Situ Ecosystem to Predict Disease Outcome
Authors: Wilson G M , Doan T B , Guild B J , Pathmanathan N , Graham J D
Published: October 2024

Disclosure: G.M. Wilson: None. T.B. Doan: None. B.J. Guild: None. N. Pathmanathan: None. J.D. Graham: None.

Mammographic screening programs have resulted in remarkable improvements in breast cancer survival due to early-stage detection. However, this has resulted in a dramatic increase in the detection of non-invasive ductal carcinoma in situ (DCIS), a non-obligate precursor of invasive ductal carcinoma (IDC), which is confined to the ducts and surrounded by a normal myoepithelial cell layer. Many DCIS cases will not progress to IDC within the lifetime of the patient. However, there are limited tools to accurately predict progression, thus virtually all DCIS is surgically removed, and most patients receive adjuvant radiotherapy as it halves recurrence rates. This likely represents overtreatment for a majority of patients. Emerging evidence has revealed that the adjacent microenvironment becomes progressively altered in DCIS and IDC compared to normal tissue, and this is correlated with disease outcome. The objective of this study was to investigate changes to the DCIS microenvironment during disease progression and identify disease states that predict patient outcome. We used immunohistochemistry and imaging mass cytometry with a well-annotated cohort of DCIS, with or without adjacent IDC, to measure a panel of 40 phenotypic and functional markers that allowed us to distinguish the diverse cell populations present in the tissues. We observed striking changes to almost all cell types within the DCIS tissue when comparing pure DCIS cases to DCIS adjacent to IDC. In particular, there were considerable changes to tissue-resident immune populations, with differences observed in the type, location and population size of a variety of immune cell subsets, in IDC-associated DCIS compared with DCIS-only cases. Computational mapping of cell type communities in pure and IDC-adjacent DCIS tissues revealed specific differences that could be used to predict the emergence of invasive disease, informing clinical management of this good prognosis malignancy and potentially avoiding over-treatment.

Presentation: 6/3/2024
8127 HOMA-IR Predicts Muscle Wasting during Androgen Deprivation Therapy
Authors: Caeiro Lucas , Jayne Anderson Lindsey , Liu Haiming , Manuel Garcia Jose
Published: October 2024

Disclosure: L. Caeiro: None. L.J. Anderson: None. H. Liu: None. J.M. Garcia: None.

Androgen deprivation therapy (ADT) is the primary treatment for advanced and metastatic prostate cancer. However, it induces adverse effects like reduced muscle mass and function, increased adiposity, and insulin resistance (IR). While muscle wasting is a known complication of ADT-induced hypogonadism, the extent to which other factors determine the variability in muscle loss remains unknown. In other diseases, IR is associated with muscle wasting, but its role in this setting of ADT has yet to be addressed. We hypothesized that patients with greater IR pre-ADT would display larger decreases of muscle mass and function after six months of ADT. Insulin and glucose (to calculate HOMA-IR), body composition, and physical function were assessed in patients with prostate cancer prior to and after three and six months of ADT. Body composition was assessed by dual x-ray absorptiometry and physical function by VO2 peak and 6-minute walk test (6MWT). Fasting blood samples were obtained to measure insulin and glucose in plasma. Pre-ADT, HOMA-IR was directly correlated with body mass index (BMI) (r=0.65, p<0.001, n=49), fat mass (r=0.55, p<0.001, n=49), and appendicular skeletal muscle index (ASMI) (r=0.33, p=0.021, n=49) and was inversely correlated with VO2 peak (r= -0.39, p=0.007, n=46). After three months, fat mass (p=0.015) and IR (p=0.0014) increased and VO2 peak decreased (p=0.0007), which persisted at the six-month visit. Appendicular lean mass and ASMI decreased after six months (p<0.0001). Pre HOMA-IR was negatively associated with delta BMI (r=-0.49, p<0.001, n=46), delta lean mass (r=-0.58, p<0.001, n=46), delta ASMI (r=-0.52, p<0.001, n=46), and delta 6MWT (r=-0.37, p=0.011, n=45) and positively correlated with delta VO2 peak (r=0.44, p=0.007, n=36). No associations were found with Pre-ADT HOMA-IR and changes in fat mass. In conclusion, those with greater Pre-ADT HOMA-IR lost more muscle mass, body weight, and 6MWT while unexpectedly showing less decrease in VO2 peak. This data suggests that HOMA-IR could potentially serve as a predictor of muscle mass loss in patients undergoing ADT. We propose that the significant decrease in muscle mass seen with ADT can be exacerbated by pre-existing IR.

Presentation: 6/3/2024
8212 Insulin Receptor Signaling and Racial Disparities in Triple Negative Breast Cancer
Authors: Engel A J , Samuel K , Bass I R , Lin S , Antoniou I , Yagnik R , LeRoith D , Bickell N A , Gallagher E J
Published: October 2024

Disclosure: A.J. Engel: None. K. Samuel: None. I.R. Bass: None. S. Lin: None. I. Antoniou: None. R. Yagnik: None. D. LeRoith: None. N.A. Bickell: None. E.J. Gallagher: Consulting Fee; Self; Novartis Pharmaceuticals.

Introduction: Obesity and type 2 diabetes are associated with poor breast cancer (BC) prognosis. These disorders, along with hyperinsulinemia are more common in Black than in White women. Black women also have higher rates of triple negative breast cancer (TNBC), and greater breast cancer mortality than White women. We hypothesized that Black women with TNBC have worse outcomes in part due to tumor promoting effects of hyperinsulinemia via the insulin receptor (IR) signaling pathway. Methods: From our IRB-approved, multi-institutional, cross-sectional, NIH-funded, study of women with newly diagnosed BC, we identified women with TNBC. We performed immunohistochemistry (IHC) analysis of formalin-fixed-paraffin-embedded tumor samples from 45 self-identified Black women and 48 self-identified White women. We quantified the BC expression of IR (n=92), IGF1R (n=92), pERK (n=91), FOXO3a (n=90) for intensity (none=0, weak=1, moderate=2, intense=3). In subsequent analysis, 0 and 1 intensity IHC staining were considered negative, and 2 and 3 were considered positive. Quantification was performed with reviewers blinded to clinical information. Clinical information (age, race, body mass index [BMI], waist circumference, fasting insulin, BC Nottingham Prognostic Index [NPI]) was evaluated after IHC scoring. Statistical proportions were compared using Fishers Exact test, and continuous variables were evaluated using parametric or non-parametric tests, as appropriate. Results: Positive IR staining was seen in 64% of samples (n=59), 74% (n=68) for IGF1R, 68% (n=62) for FOXO3a and 43.3% (n=39) for pERK. Positive IR staining was more prevalent in Black women than White women (P=0.003) but was not significantly associated with age or NPI. IGF1R, FOXO3a, pERK positive staining were not associated with race or NPI. Positive IR staining was also associated with higher BMI, waist circumference, and fasting insulin (P<0.05 for all). Positive IGF1R, FOXO3a, pERK staining were not associated with any of these factors. Conclusions: We found that 64% of TNBCs had positive expression of IR, and IR expression was more prevalent in tumors from Black women and associated with higher insulin levels, suggesting that tumors from Black women may be more sensitive to the tumor promoting effects of systemic hyperinsulinemia.

Presentation: 6/2/2024
7948 Integration of Epigenomics and Metabolomics Reveals New Signaling in Aggressive Thyroid Cancer
Authors: Sanghi A , Wu S , Chou T , Orloff L A , Kasowski M , Snyder M
Published: October 2024

Disclosure: A. Sanghi: None. S. Wu: None. T. Chou: None. L.A. Orloff: None. M. Kasowski: None. M. Snyder: None.

Although genetic mutations are causal in human cancers, the contribution of chromatin changes to cancer onset and progression remains less well understood. Multi-omics profiling of human tumors can provide insight into how alterations in chromatin structure are propagated through the pathway of gene expression to result in cancer signaling. We applied multi-omics profiling of 36 human thyroid cancer primary tumors, metastases, and patient-matched normal tissue. Over 80% of the tumors harbored BRAFV600E mutations, and the remaining tumors mostly had activating mutations in the MAPK pathway. Through quantification of chromatin accessibility associated with active transcription units and global protein expression, we identify local enhancers that are highly correlated with coordinated RNA and protein expression. The enhancers are predicted to be actively bound by MAPK transcription factor, indicating they are under MAPK control. These cancer-specific enhancers associated with upregulation of lysosomal peptidase expression and dipeptide abundance in tumors. We show that upregulated dipeptides stimulate MAPK activity, and BRAF inhibition results in loss of lysosomal function in mutants. Perturbation of lysosomal peptidases and dipeptide abundance decreases MAPK activity only in mutant cells compared to wildtype. These analyses suggest that BRAF thyroid tumors integrate MAPK-driven epigenetic regulation with lysosomal metabolite signaling in a positive feedback circuit. Using local cancer-specific epigenetic features, we isolated key cancer signaling, making way for potential targets for cancer therapeutics.

Presentation: 6/3/2024