bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extracellular cleaved HER2 (p95) confers partial resistance to trastuzumab but not HSP90 inhibitors in models of HER2 amplified breast cancer
Authors: Chandarlapaty S. , Scaltriti M. , Baselga J. , Ye Q. , Solit D. , Norton L. , Rosen N. 
Published: March 2020

10515 Background: Breast cancers containing an amplified copy of the HER2 receptor tyrosine kinase represent 20–30% of all cases and antibody directed therapy targeting the extracellular domain of HER2 with trastuzumab has proven broadly efficacious. However, resistance to trastuzumab is a common phenomenon. Recent work has identified a cleaved, 95kD version of HER2 that lacks the extracellular epitope in which the trastuzumab binding site is found. Presence of this so called “p95” has been correlated with a worse clinical prognosis. We hypothesized that p95 may enable tumor resistance to trastuzumab. Methods/Results: We established models of p95 expressing breast cancer by transfecting p95 into preexisting models of HER2 amplified breast cancer. We find that cells expressing p95 display increased resistance to the growth inhibitory effects of trastuzumab. The PI3K-AKT pathway that is downregulated by Trastuzumab is less affected in the p95 expressing cells. Furthermore, p95 demonstrates an association with HER3 that is unaffected by trastuzumab treatment. Next, we evaluated the efficacy of therapies targeted against the intracellular domain of HER2 such as the HSP90 inhibitor, 17-AAG. HER2 requires HSP90 for its conformational stability and inhibitors of HSP90 result in growth inhibition of HER2+ breast cancer. We find that p95 displays a similar requirement for HSP90 as inhibitors of HSP90 result in the degradation of p95. Moreover, cells overexpressing p95 are equally susceptible to the antitumor effects of HSP90 inhibitors as those without high levels of p95. Finally, we utilized an empirically derived, in vivo model of trastuzumab resistance that displays high level expression of p95. As with the transfected models, these tumors retain their sensitivity to HSP90 inhibitors as treatment of mice bearing tumors results in both degradation of HER2 and p95 as well as robust tumor growth inhibition. Conclusions: Given the presence of p95 in human breast tumor samples, the data suggest that p95 may play an important role in mediating clinical resistance to trastuzumab. They further suggest that such tumors may retain their sensitivity to targeted therapy against the intracellular portion of HER2 such as with lapatinib or 17-AAG. No significant financial relationships to disclose.
Phase II trial of nab-paclitaxel (nanoparticle albumin-bound paclitaxel (ABX)) + capecitabine (XEL) in first-line treatment of metastatic breast cancer (MBC)
Authors: Somer B. G. , Schwartzberg L. S. , Arena F. , Epperson A. , Fu D. , Fortner B. V. 
Published: March 2020

1053 Background: ABX and XEL both have substantial single agent activity in MBC. Taxane and anti-metabolite doublets improve response rate and TTP and longer survival. ABX administered weekly has an excellent safety and efficacy profile with maintenance of dose intensity. This study was designed to test the safety and efficacy of ABX + XEL given in a novel combination schedule. Methods: This phase II, multicenter open label study utilized ABX 125 mg/m2 IV on day 1, 8 and with no premeds and capecitabine 825 mg/m2 PO BID days 1–14 on a Q 3 week cycle. The primary endpoint is objective response rate, with evaluation performed after every 2 cycles. Entry criteria include measurable MBC by RECIST criteria, age >18, PS 0–2, no prior chemo for metastatic disease, > 6 months since adjuvant fluoropyrimidine and/or paclitaxel. Results: The full sample of 50 patients (pts) have been enrolled; data from 43 pts are available for analysis. Median age is 58 (range 23.7–90.6). 37% received prior adjuvant anthracycline and 33% prior adjuvant taxane. Median number of metastatic sites is 2 (range 1–7), with most common sites of disease liver, 53.5%; bone, 51.2%; and lung, 14%. 226 cycles of therapy have been delivered. 5 pts required a dose reduction in XEL (3 pts to 650 mg/m2; 2 to 550 mg/m2) and 4 pts had dose reduction in ABX to 100 mg/m2. XEL dose reductions occurred due to hand-foot syndrome (3), neutropenia (1), and fatigue (1). ABX dose reductions occurred due to mucositis, diarrhea, fatigue, and neuropathy (1 pt each). 10 pts had grade 3–4 non-hematologic AEs: 3 hand-foot syndrome, 4 fatigue, and 3 GI. Hematologic AEs included 4 with grade 3 and 1 with grade 4 neutropenia, and 2 with grade 4 febrile neutropenia. The most common AEs of any grade were GI (30), dermatological (23), fatigue (15), neuropathy (12), and hand-foot syndrome (11). The incidence of Grade 1–2 neuropathy was 25% (no grade 3–4). Of 38 pts available for analysis of response, the overall response rate is 47.5%: PR 39.5%, CR 8%. Total of 15 pts have stable disease, 20 pts have completed 6+ cycles. No significant financial relationships to disclose.
Therapeutic starvation and autophagy in prostate cancer: A new paradigm
Authors: DiPaola R. S. , Dvorzhinski D. , May M. , Morton R. , Foran D. , Bray K. , Karp C. , White E. 
Published: March 2020

10530 The metabolic fragility of cancer cells is magnified with the preferential utilization of glycolysis that metabolizes glucose inefficiently rather than oxidative phosphorylation (the “Warburg effect”) and from impaired mechanisms of survival. In fact, one pathway by which cells survive metabolic stress is thought to be autophagy, a catabolic process of organelle digestion, which creates ATP during periods on nutrient limitation. Remarkably, autophagy is often impaired in human prostate cancers, due to either activation of the PI-3 kinase/Akt/mTOR pathway, which normally inhibits autophagy, or through allelic loss of the essential autophagy gene beclin1. This suggests that prostate cancers may be susceptible to metabolic stress that can be exploited therapeutically. Using immortalized mouse epithelial prostate cells, as well as PC-3 and LNCaP cell lines, we demonstrated the cytotoxic effect of 2-deoxyglucose (2DG), as an inhibitor of glycolysis. We found that 2DG induced membrane translocation in cells characteristic of autophagy using a transfected pEGFP-LC3 autophagy marker construct. We then demonstrated that induction of autophagy was dependent on Beclin1 expression in these cell models using Beclin1 siRNA. Based on these data, we initiated a phase I/II clinical trial with 2DG in patients with advanced malignancies and prostate cancer, which is now ongoing. In an effort to develop markers of autophagy for assessment in a clinical trial, we stained a human prostate TMA (>35 patient cores) for Beclin1 by IHC. Beclin1 staining was increased in tumor tissue compared to normal tissue. Staining was imaged and digitized using a 40x volume scan on a high- throughput MedMicro whole slide scanner. The imaged specimens were stored in multi-tiled TIFF format on a redundant array of independent devices (RAID); staining will be analyzed using a color decomposition algorithm and compared to tumor characteristics as we have previously done (Foran DJ et al., IEEE Trans Inf Technol Biomed, 8:89–96, 2004). These data further support the rationale to inhibit metabolism in cancer and the potential importance of autophagy with metabolic approaches to therapy. Further imaging assessment and analysis of markers of autophagy such as Beclin1 are ongoing. No significant financial relationships to disclose.
Circulating tumor cells (CTC): Assessment of treatment efficacy in metastatic breast cancer (MBC)
Authors: Liu M. C. , Shields P. , Isaacs C. , Warren R. , Cohen P. , Wilkinson M. , Zhang Y. , Shen R. , Luyegu K. , Gallagher A. L. 
Published: March 2020

10535 Background: Preliminary data in MBC suggest that ≥5 CTC/7.5 mL blood is associated with worse progression free survival (PFS) and overall survival (OS), and that the persistence of ≥5 CTC/7.5 mL blood after the initiation of therapy predicts for treatment failure (NEJM 2004. 351:781.). We are conducting a prospective clinical research study to validate the prognostic and predictive significance of this serum biomarker in MBC. Methods: Serial CTC levels are obtained in patients starting a new systemic treatment regimen for progressive, radiographically measurable MBC. 10 mL samples of peripheral blood are collected before the start of treatment and then at 3–4 week intervals. All subjects are followed prospectively for PFS and OS, and they are offered the opportunity to continue CTC testing upon disease progression. CTC enumeration is performed on a 7.5 mL blood volume using the CellSearch technology (Veridex, LLC; Warren, NJ). Epithelial cells are immunomagnetically separated and fluorescently labeled, and nucleated (DAPI+) cells with the EpCAM+, cytokeratin 8/18/19+, and CD45- phenotype are counted as CTC. Clinical outcomes are based on radiographic studies and physical examination in accordance with RECIST criteria. Results: 46 of 100 subjects have been accrued, and 33 have completed at least one radiographic staging evaluation with a median follow up of 7 mos (range 2–18 mos). Treatment for the 33 evaluable patients includes chemotherapy (27%), endocrine therapy (46%), and combination therapy with a biologic agent (27%). At baseline, 85% (28/33) had at least 1 CTC/7.5 mL (range 1–78), and 27% (9/33) had ≥5 CTC/7.5 mL. Median PFS was 2.57 months and 6.77 months for subjects with ≥5 vs <5 CTC/7.5 mL at baseline, respectively (p=0.02). Conclusions: The current data validate the observation that baseline CTC levels correlate with PFS in patients with MBC and measurable disease. Patient accrual and data analysis are ongoing to confirm that persistent CTC levels ≥5/7.5 mL correlate with a lack of treatment efficacy and therefore are a reliable surrogate marker of disease responsiveness and PFS. [Table: see text]
Characterization of the pathogenic mechanism of a novel BRCA2 variant in a Chinese family
Authors: Kwong A. , Wong L. P. , Chan K. , Ma E. , Khoo U. S. , Ford J. M. 
Published: March 2020

10541 Background: Despite the identification of a large number of sequences in BRCA1/2 mutation analyses, many genetic alterations are classified as variants of unknown significance (VUS). Increasing data demonstrates ethnic variation of BRCA mutation. We report a novel BRCA2 VUS in a Chinese family with multiple breast cancers and characterized it as pathogenic by RNA analysis. Method: Peripheral blood was collected from the breast cancer proband and her family who were suspected to have a pathogenic mutation due the segregation of the disease phenotype and the young age of presentation of breast cancer. DNA and RNA was extracted from the blood. The entire coding regions and flanking introns of BRCA1/2 were screened for germline mutations using full gene sequencing and Multiplex Ligation -dependent Probe Amplification. Variant DNA alteration leading to an aberrant BRCA transcript was demonstrated by RT-PCR of the RNA and Polyacrylamide Gel Electrophoresis. Abnormal bands were cloned and direct sequencing conducted. Results: A germline mutation c.7806–9T>G was identified in the proband at the BRCA2 intron 16. This mutation was also found in 3 of her 4 sibling sisters with early breast cancer. The proband's mother harbored the same BRCA2 mutation in DNA extracted from archival gastric tumor tissues. Computational analyses showed that this mutation might give rise to a cryptic splice site for alternative RNA splicing. To confirm the pathogenicity, RT- PCR using specific primers flanking the cryptic splice site and sequencing was performed on RNA extracted from the proband's blood. Four different sizes of transcripts were found: wild type, r.7806_7874del , r.7806_7976del and r.7806–8_7806-lins. The latter 3 aberrant transcripts were not found in the 30 controls therefore polymorphism is unlikely. The r.7806–8_7806-lins transcript caused a frameshift which created a truncated protein; whereas the other two short transcripts produced shorter BRCA2 protein isoforms. Conclusion: We identified a novel BRCA2 VUS and classified it as pathogenic. Classification of VUS as neutral or pathogenic, particularly in ethnic groups where limited knowledge is known is a challenge. Research on the spectrum of mutations in diversed ethnic groups has important implications on management. [Genbank: DQ889340 ] No significant financial relationships to disclose.
Impact of E27X cdkn2a mutation on p16 and p14arf expression in melanoma families and pancreatic cancer
Authors: Queirolo P. , Ghiorzo P. , Gargiulo S. , Gliori S. , Acquati M. , Boitano M. , Bodini G. , Segalla V. , Pugliese V. , Fornarini G. , Bianchi Scarrà G. 
Published: March 2020

10543 Background: Mutations in the CDKN2A gene underlie melanoma susceptibility in as many as 50% of melanoma kindreds in selected populations, and several CDKN2A founder mutations have been described. Inherited mutations in CDKN2A have been found to be associated with other non-melanoma cancers including pancreatic cancer and neural system tumours. Here we report a novel germline mutation in exon 1 of the CDKN2A gene, E27X, which we first detected in melanoma patients living in or originally from a small geographic area bordering Liguria, in north-western Italy. A subset of melanoma kindreds positive for this mutation displayed pancreatic cancer and neuroblastoma. Methods: We investigated 70 pancreatic cancer patients from a case-control study living in or originally coming from a small geographic area bordering Liguria, in north-western Italy, for CDKN2A mutations and ARF. Results: 2 out of 70 patients displayed the E27X mutation and 1 of the 2 patients had a first degree relative affected by pancreatic cancer. Conclusions: E27X generates a premature stop codon, leading to dramatically reduced protein levels of p16 and leaving p14ARF unaltered. As pancreatic cancer and neural system tumours have been postulated to be preferentially associated with CDKN2A mutations located in exon 2 and/or affecting p14ARF alone, the position of E27X in exon 1a provides interesting insights towards clarifying the mechanisms by which the CDKN2A/ARF locus is involved in cancer predisposition. Its finding in pancreatic cancer patients confirms common susceptibility to melanoma and pancreatic cancer due to this CDKN2A exon 1 mutation. No significant financial relationships to disclose.
Validation of the PREMM1,2 model for the prediction of MLH1/MSH2 germline mutation carriers in a population- based cohort of colorectal cancer (CRC) patients
Authors: Balmaña J. , Balaguer F. , Steyerberg E. W. , Stoffel E. M. , Castellví-Bel S. , Andreu M. , Castells A. , Syngal S. 
Published: March 2020

10545 Background: PREMM1,2 is a predictive model for estimating the likelihood of finding a mutation in the MLH1 and MSH2 genes developed in a population at risk of Lynch syndrome (Balmaña et al. JAMA 2006). The EPICOLON cohort is a Spanish population-based series of 1222 patients with CRC (Piñol et al. JAMA 2005). Methods: All 1222 individuals underwent microsatellite instability (MSI) and immunohistochemistry (IHC) analysis for MLH1/MSH2. Patients whose tumours exhibited MSI or altered IHC underwent MLH1/MSH2 analysis (n=91). Sensitivity (Se), specificity, positive predictive value (PPV), and the areas under the receiver operating characteristics curves (AUC) for the PREMM1,2 model were calculated and compared with the Edinburgh model (Barnetson et al. NEJM 2006) and the Revised Bethesda guidelines (RBG). Results: Three-hundred and ninety six individuals (32%) had a PREMM1,2 score =5%, 287 (23%) fulfilled the RBG, and 75 (6%) had a Barnetson score =5%. A PREMM1,2 score =5% and the RBG identified all carriers with deleterious mutations (n=8, Se=100%), while a Barnetson score =5% missed 2 mutation carriers (Se= 75%). For PREMM1,2 and Barnetson scores =5% and fulfilment of the RBG, specificities were 68%, 94%, and 77%, respectively; and PPV were 2%, 8%, and 2.8%, respectively. The AUC was 0.93 (95% CI: 0.86–0.99) for the PREMM1,2 model and 0.86 (95% CI: 0.66–1.04) for the Barnetson model. The predictions of carrying a mutation stratified into five groups based on PREMM1,2 scores (<5%, 5–9%, 10–19%, 20–39%, =40%) correlated reasonably with the presence of mutations (0%, 1%, 1%, 13%, and 22%, respectively). Conclusions: In a population of CRC patients, the PREMM1,2 model identifies all mutation carriers of MSH2 and MLH1 using a cutoff of =5%. In addition, it provides quantification of risk that is useful to decide the strategy used for molecular evaluation and risk counselling of patients. No significant financial relationships to disclose.
Characterization of concurrent ovarian and endometrial carcinoma by copy-number analysis (CNA) and gene expression profiling (GEP)
Authors: Guirguis A. , Elishaev E. , Timms K. , Reid J. , Abkevich V. , Gutin A. , Launchbury J. , Zorn K. , Deloia D. 
Published: March 2020

10546 Background: Coexistence of endometrioid carcinoma at both sites, the ovary and the endometrium, is between 10–30%. Current staging relies on clinical and pathologic assessment, which is not quantitative and highly subjective. The objective of this study was to evaluate archived tissues from patients with concurrent tumors for CNA and GEP, and determine if either or both of these techniques could be used to define the primary site of the endometroid carcinoma. Methods: A gynecologic pathologist confirmed that all specimens from both sites were of endometrioid histology; grades I/II. CNA was determined by extracting DNA from both disease and non-disease tissues for hybridization to the Affymetrix 500K SNP microarrays. Illumina HumanRef8 BeadChip microarrays were used throughout to obtain GEP for 7 endometrial and 7 ovarian primary stage I tumor samples. Differentially expressed genes between both groups created a corresponding discrimination scores (DS). The performance of the discrimination scores were evaluated by the Leave-One-Out method. In a similar fashion, a test set of 16 tumor samples from patients with concurrent tumors were profiled. The prediction of these tumors’ origin based on the DS were compared with pathological assessment and copy number analysis. Results: Concurrent tumors display more copy number changes than singular tumors of either tissue, with a greater fraction of the genome involved. Analysis of the non-affected tissue assists in identifying tumor-specific changes. We identified a set of 30 differentially expressed genes between both ovarian and endometrial tumors that discriminates a tumors’ origin with about 80% confidence. For patients with concurrent tumors, comparison of their origin based on GEP, CNA, and pathological assessment shows limited concordance. Conclusion: Shared somatic copy number changes in simultaneous endometrioid carcinomas of the ovary and endometrium indicate a common origin and hence metastasis. For these relatively common concurrent tumors, clinical inferences based on CNA appear more robust than those based on GEP, and more objective than pathological assessment. No significant financial relationships to disclose.
Pathologic predictors of BRCA1/ BRCA2 (B1/B2) mutations in African-American (AA) women with early-onset breast cancer (BC)
Authors: Domchek S. M. , Simon M. S. , Hughes Halbert C. , Rebbeck T. R. , Nathanson K. L. 
Published: March 2020

10549 Background: African-American (AA) women more frequently have “triple negative” (ER-, PR-, HER2-) breast cancer (BC) and such BC are more frequently associated with B1 mutations; however, the correlation of triple negative BC in the AA population and B1/2 mutations is not known. We were interested in examining the prevalence of B1/2 mutations in a cohort of AA with early-onset breast as well as the associated pathologic characteristics. Methods: 85 unselected AA women diagnosed with 88 BC at or prior to age 40 were enrolled on study and underwent BRCA1/2 genetic testing by full sequencing at Myriad Genetics following informed consent. MLPA screening for large genomic rearrangements also was performed. Pathology reports were obtained and examined. Results: Of the 85 women, 16 (19%) had either a B1 (11) or B2 (5) deleterious mutation, which were associated with 19 BC. 19/85 (22%) women had a variant of unknown significance (VUS); 3 had B1 VUS, 15 had B2 VUS (including 2 with B1 mutations) and 1 had both B1 and B2 VUS. No mutations were detected with MLPA. Of the 14 BC in 11 B1 mutation carriers, 12 were ER- (86%), 13 were PR- (93%) and 3/12 were HER2+ (25%). Of the 5 BC in B2 carriers, 4 were ER- (80%), 1/4 HER2+ (25%). Receptor status was available in 77 of 88 cases (88%). Overall 41 of 77 (53%) cancers were ER-. 15 of 40 women (38%) with any ER- BC had either a B1 (11) or B2 (4) mutation. In contrast, of the 36 ER+ BC, 2 had a B1 and one had a B2 mutation (8%) (p=0.01). Both B1 carriers with ER+ BC also had a contralateral ER- BC. 18 of 65 (27%) cancers were known to be HER2+, of which 4 of 18 (22%) were associated with B1 or B2 mutations (p=NS). Median age of first BC in B1/B2 mutation carriers was 32 vs. 37 in non-carriers. Conclusions: In unselected AA women with early onset BC, B1/2 mutations were common and predominantly found in association with ER- BC. B2 VUS were detected frequently. HER2 overexpression did not predict against B1/2 mutations. No significant financial relationships to disclose.
Trastuzumab (T) plus capecitabine (C) in heavily pretreated patients (pts) with advanced breast cancer (ABC)
Authors: Bartsch R. , Wenzel C. , Altorjai G. , Pluschnig U. , Locker G. J. , Rudas M. , Mader R. M. , Zielinski C. C. , Steger G. G. 
Published: March 2020

1055 Background: In pts with Her2 positive ABC, taxane or vinorelbine plus T are among the most widely applied options in the first line setting. We evaluated the efficacy and tolerability of TC in pts with Her2 positive ABC after anthracycline and docetaxel or vinorelbine failure. Methods: Forty consecutive pts (median age 57.5 years) were included. As of December 2006, all are evaluable for toxicity and 35 for response. C was administered at a daily dose of 2,500 mg for two consecutive weeks (w) every 3 w, with dose modifications if necessary. T was administered in 3 w cycles at a dose of 6 mg/kg bodyweight after a loading dose of 8 mg/kg. Time to progression (TTP) was defined as primary endpoint. Response was evaluated every three months (m) using UICC criteria. TTP and overall survival (OS) were estimated using the Kaplan-Meier product limit method. Differences in TTP for 2nd line and beyond 2nd line were analyzed with the log-rang test. Results: All pts had prior exposure to an anthracycline and at least one anti-microtuble agent (i.e. a taxane or vinorelbine). All had at least one earlier T containing treatment line for ABC. Median time of observation was 18.5 m. We observed a complete response in 2.9%, partial response in 20%, stable disease = 6 months in 48.6%, and progression in 28.6% of pts. OS was median 24 m (95% CI 20.3–27.7), and TTP 8 m (95% CI 5.8–10.1). No significant difference was found for 2nd and beyond 2nd line treatment. Diarrhoea (5%) and hand foot syndrome (16%) were the only treatment-related adverse events that occurred with grade 3 or 4 intensity. A dose reduction was necessary in 22.5%. Two pts developed brain metastases (BM) while on therapy, 6 had BM at time of treatment initiation, a further 5 developed BM during follow up. Of 6 pts with BM, 3 gained clinical benefit from treatment (one pt not yet evaluable). Conclusions: TC appears to be an effective and safe option as salvage therapy in a heavily pretreated population. TTP and response rates are similar to results from C plus lapatinib. Of note is the activity in pts with BM. Further, only 2 pts (5%) developed BM while on treatment. Therefore, a direct comparison of TC with C plus lapatinib or T plus lapatinib seems warranted. No significant financial relationships to disclose.