bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P2-01-26: Validation of a Chinese nomogram with a Dutch breast cancer population: Excellent prediction of the probability of axillary lymph node metastasis
Authors: Qiu S-Q , Aarnink M , van Maaren MC , Dorrius M , Koffijberg H , van Dam GM , Siesling S
Published: March 2017

Background: In the era of precision medicine, the surgical management of axillary lymph nodes (ALN) should be patient-tailored. Omission of sentinel lymph node biopsy (SLNB) is possible in patients with early breast cancer and very low or very high probability of ALN metastasis. Recently, we developed a nomogram to predict the probability of ALN metastasis in breast cancer patients based on clinicopathological parameters including ultrasound using a Chinese patient dataset1. In this study the nomogram performance was validated in an independent Dutch population from one hospital.

Methods: Data of 170 Dutch patients with a successful SLNB or axillary lymph node dissection were collected. A lymph node containing either micro- or macrometastatic disease was considered as a positive lymph node. Performance of the nomogram was assessed by calculating the area under the receiver-operator characteristic (ROC) curve (AUC). False-negative rates (FNRs) and false-positive rates (FPRs) at several different predictive cut-off points were calculated.

Results: There were 69 (40.6%) patients having a positive ALN. The AUC for the nomogram was 0.84 (95% confidence interval 0.78-0.90) compared with 0.86 in the Chinese validation population, showing excellent discrimination of the model. The FNR and FPR of the model were 10.2% and 0% for the predicted probability cut-off points of 14.5% and 90%, respectively.

Table 1 False-negative rates (FNRs) and false-positive rates (FPRs) of the nomogram at different predictive cut-off pointsPredicted rishPatient number and percentage (%)Number of patients with positive ALNFNR (%)< 14.5%59 (34.7)610.2< 20%79 (46.5)1113.9  Number of patients with negative ALNFPR (%)> 70%27 (15.9)13.7> 90%18 (10.6)00ALN: axillary lymph node

This means that omission of SLNB is possible for patients with a predictive probability of less than 14.5% or higher than 90%, which accounts for 45.3% of all patients in this study.

Conclusions and future perspectives: In this study, the Chinese nomogram showed excellent performance in predicting the probability of ALN metastasis in an independent Dutch population. A multicentre validation of this nomogram in large Dutch patient population (>2500 patients) is ongoing.

Reference

1.Qiu S-Q, Zeng H-C, Zhang F, et al. A nomogram to predict the probability of axillary lymph node metastasis in early breast cancer patients with positive axillary ultrasound. Sci Rep 2016; 6: 21196.

Citation Format: Qiu S-Q, Aarnink M, van Maaren MC, Dorrius M, Koffijberg H, van Dam GM, Siesling S. Validation of a Chinese nomogram with a Dutch breast cancer population: Excellent prediction of the probability of axillary lymph node metastasis [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-01-26.
Abstract P2-01-36: Ex vivo shear-wave elastography of axillary lymph nodes predicting nodal metastasis in patients with primary breast cancer: A pilot study
Authors: Lim JW , Lee HW , Park JT , Ahn SG , Jung J
Published: March 2017

Objective: To evaluate the feasibility of shear-wave elastography using breast ultrasonography in identifying metastasis of removed sentinel lymph nodes during the operation for treatment of breast cancer.

Background: Conventional method for identification of sentinel nodal metastasis is time and cost consuming. The optimal method for identification of nodal status is important.

Methods: Excised sentinel lymph nodes during the operation were prospectively examined with the elastography. Metastatic status of lymph nodes was confirmed with permanent histology. Only macrometastasis was regarded as positive. Elastic values measured by the ex vivo elastography and nodal characteristics were analyzed to correlate with nodal metastasis.

Results: A total of 274 lymph nodes harvested from 68 breast cancer patients at Gangnam Severance Hospital from May 2014 to April 2015 were included this study. There was the difference of elastic values between nodes with and without metastasis (mean stiffness, 41.6 kPa and 17.4 kPa, P < 0.001). Mean sizes of metastatic nodes (range 0.36-2.59 cm) were significantly larger than that of non-metastatic nodes (1.0 cm versus 0.75 cm, P < 0.001). Moreover, there was a correlation between the size of metastatic nodes which ranged from 0.7 to 21.5 mm with a median of 7 mm and nodal stiffness (correlation coefficient of mean stiffness, r = 0.431). The area under the receiver operating characteristic curve (AUC) by the mean stiffness was 0.794. The combination of size of nodes, mean stiffness and ratio made AUC of 0.856.

Conclusions: In our study, ex vivo shear-wave elastography of sentinel lymph nodes was a feasible method to predict metastasis. Through the validation study, ex vivo elastography could be helpful to determine metastasis of sentinel lymph nodes during the operation.

Keywords Breast cancer; Elastography; Lymph node metastasis.

Citation Format: Lim JW, Lee HW, Park JT, Ahn SG, Jung J. Ex vivo shear-wave elastography of axillary lymph nodes predicting nodal metastasis in patients with primary breast cancer: A pilot study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-01-36.
Abstract P2-02-01: Identifying the remaining causes of hereditary breast cancer
Authors: Campbell IG , Trainer AH , Devereux L , James PA , Rowley S , Li N
Published: March 2017

Identifying the missing hereditary factors of familial breast cancer could have a major and immediate impact on reducing breast cancer risk in these family members.

Up to 1,325 candidate breast cancer predisposition genes, identified through exome sequencing of BRCAx families, were sequenced in index cases of up to 4,000 BRCAx families and 4,000 cancer free women from the LifePool study in Australia.

Interrogation of the data to refine the highest priority candidates is ongoing, but it is noteworthy that known (PALB2) or suspected (MRE11A) moderately penetrant breast cancer genes showed enrichment of loss of function (LoF) mutations in this dataset. Conversely, some other recently proposed breast cancer genes (BRIP1 and RINT1) did not show a significantly higher LoF mutation frequency in the cases compared to controls. Based on the number of LoF mutations leading candidates include NTHL1 (12 cases versus 4 controls) and ALKBH1 (7 cases versus 2 controls) which are each important members of the base excision repair and direct nucleotide repair pathways. We examined other genes in the base excision and direct repair pathways that were on our sequencing capture design and observed a significant enrichment of potentially deleterious mutations in 12 genes (NTHL1, OGG1, APEX1, APEX2, NEIL1, NEIL2, NEIL3, MUTYH, MPG, ALKBH1, ALKBH2, ALKBH3): Among the 1,638 cases and 1,654 controls analysed to date, 76 LoF variants were detected in these genes among the cases versus 47 LoF variants among the controls (p=0.007). Based on the overall distribution of variants between cases and controls the probability of selecting 12 genes with such enrichment from the 1,325 genes screened was less than 1 in 200.

Our data implicates rare mutations in base excision and direct DNA repair pathways genes as moderate-penetrance breast cancer susceptibility alleles.

Citation Format: Campbell IG, Trainer AH, Devereux L, James PA, Rowley S, Li N. Identifying the remaining causes of hereditary breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-02-01.
Abstract P2-03-02: Differential mutation pattern between neoadjuvant and metastatic settings in breast cancer patients
Authors: Xu B , Williams C , De P , Dey N , Klein J , Williams K , McMillan A , Leyland-Jones B
Published: March 2017

Background: Dysregulated signaling pathways occur in human cancers including breast cancer, making it a rational target for novel genome guided combinatorial personalized therapies. The aim of the present study was to investigate the different genetic mutation pattern between neoadjuvant and metastatic settings in breast cancer patients to guide research and clinical treatment.

Material and Methods: 150 breast cancer patients were involved in this study. 38 patients were receiving neoadjuvant treatment and 112 patients were in the metastatic setting. Tumor specimens obtained from the 150 patients were subjected to genetic mutation testing by FoundationOne. Genetic alterations detected by FoundationOne test were collected and analyzed.

Results: 96 and 149 different genes where reported by FoundationOne in neoadjuvant and metastatic setting respectively. The average number of non-synonymous mutation was five per case in the neoadjuvant setting and six per case in the metastatic setting. TP53 (58%), MYC (32%), PIK3CA (29%), PTEN (16%), CDH1 (13%), CCND1 (11%), EMSY (11%), LYN (11%) and ZNF703 (11%) were the most seen mutations in neoadjuvant setting. TP53 (40%), PIK3CA (39%), MYC (22%), CCND1 (21%), FGF19 (21%), FGF4 (21%), CDH1 (20%), FGF3 (19%), ERBB2 (17%), ESR1 (14%), FGFR1 (14%), ZNF703 (14%), GATA3 (13%), MYST3 (11%), PTEN (11%), EMSY (10%), NF1 (10%) and ZNF217 (10%) were the most seen mutations in metastatic setting. ESR1 and GATA3, which are seen in 14% and 13% of metastatic breast cancer patients, were not reported in neoadjuvant breast patients. Moreover, among the 16 metastatic breast cancer patients who has ESR1 mutation, 9 (56%) of them presented with PIK3CA or other genetic mutations which are directly involved in the phosphoinositide 3-kinase (PI3K)/AKT pathway.

Conclusion: A significantly more mutation in Receptor Tyrosine Kinases (RTKs)/ Growth Factor Signaling ( especially ERBB and FGFR pathways) was reported in the metastatic setting compare to the neoadjuvant setting, suggesting a critical role of the RTKs in metastatic breast cancer patients. The coexisting of ESR1 and PI3K/AKT pathway alteration and the absence of ESR1 in neoadjuvant setting also suggested that in early stage breast cancer patients who have a PI3K pathway alterations; there is a higher chance to develop ESR1 mutation with disease progression.

Citation Format: Xu B, Williams C, De P, Dey N, Klein J, Williams K, McMillan A, Leyland-Jones B. Differential mutation pattern between neoadjuvant and metastatic settings in breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-03-02.
Abstract P2-04-21: Suppression of immune response by X-linked inhibitor of apoptosis protein-nuclear factor kappa-light-chain-enhancer of activated B cells tumor cell signaling
Authors: Sauer SJ , Evans MK , Morse MA , Devi GR
Published: March 2017

This abstract was withdrawn by the authors.
Abstract P2-05-15: The lymph node ratio as an independent prognostic factor for node-positive triple-negative breast cancer
Authors: He M , Jiang Y-Z , Tang L-C , Chen Y-L , Shao Z-M , Di G-H
Published: March 2017

Purpose: To evaluate the prognostic value of the lymph node ratio (LNR) in patients with axillary lymph node-positive triple-negative breast cancer (TNBC).

Patients and methods: Based on X-tile plots, we classified women into low-, medium-, and high-risk LNR groups. Univariate and multivariate Cox proportional hazards regression analyses for overall survival (OS), breast cancer-specific survival (BCSS) and disease-free survival (DFS) were performed. The prognostic efficacy of the LNR was investigated in the first cohort from the Surveillance, Epidemiology, and End Results (SEER) database (n=4114) and was further validated in an independent cohort from Fudan University Shanghai Cancer Center (n=417).

Results: The patients were classified into low- (≤0.30), medium- (0.30 to 0.70) and high-risk (>0.70) LNR groups. Multivariate analysis revealed that the LNR was an independent predictor of OS (hazard ratio (HR) for high-risk LNR: 3.24; 95% confidence interval (CI): 2.56 to 4.09) and BCSS (HR for high-risk LNR: 3.57; 95% CI: 2.76 to 4.62) in the SEER population and also for DFS (HR for high-risk LNR: 4.29; 95% CI: 2.24-8.21) in the validation population. Subgroup analysis revealed that patient classification according to the LNR could discriminate among groups of patients with different survival rates based on pN staging.

Effect of Lymph Node Ratio and pN Classification on Survival Among Patients from SEERVariableOSBCSS HR a(95% CI)PHR a(95% CI)PLymph node ratio    Low,≤0.301-1-Medium, >0.30 and ≤0.702.05(1.63-2.59)<0.0012.26(1.75-2.92)<0.001High,>0.703.24(2.56-4.09)<0.0013.57(2.76-4.62)<0.001pN    N11-1-N21.53(1.21-1.93)<0.0011.63(1.27-2.10)0.001N32.72(2.14-3.46)<0.0012.97(2.29-3.85)<0.001a Cox proportional hazards model. Hazard ratios are adjusted for age, race, histologic grade, tumor size, surgery type and radiotherapy.

Conclusion: The LNR shows potential for use as an additional prognostic factor for TNBC patients with positive lymph node involvement. Considering the heterogeneity of TNBC, use of the LNR might allow for optimization of the pN staging system, and this ratio should be considered when making treatment decisions.

Citation Format: He M, Jiang Y-Z, Tang L-C, Chen Y-L, Shao Z-M, Di G-H. The lymph node ratio as an independent prognostic factor for node-positive triple-negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-15.
Abstract P2-05-29: The molecular subtype has greater influence on prognosis of breast cancer than age at diagnosis
Authors: Kim HS , Eom YH , Song BJ , Chae BJ
Published: March 2017

This abstract was withdrawn by the authors.
Abstract P2-05-38: Spectral CT based radiomics signature: A potential biomarker for preoperative prediction of lymph node metastasis in breast cancer
Authors: Dong D , Zhang X , Fang M , Shen J , Tian J
Published: March 2017

Purpose:

To investigate the usefulness of radiomics signature based on computed tomographic (CT) spectral imaging, during the late arterial phase (AP) and portal venous phase (PVP), in preoperative predicting the lymph node (LN) metastasis in breast cancer (BC).

patients and methods:

This retrospective study was institutional review board approved, and written informed consent was obtained from all patients. We examined 60 female patients (LN metastasis positivity was 50%) with CT spectral imaging during the AP and the PVP and data was gathered from 2014 to 2016. Excised lymph nodes were located and labeled during surgery according to location on preoperative CT images and were evaluated histopathologically. For each patient, two 3D Hounsfeld Unit (HU) gradient maps which revealed the HU change of each voxel were built by quadratic fitting the spectral HU curves during the two phases respectively. Then the radiomics features were then extracted from the regions of BC and a suspicious LN judged manually in these maps. The potential association of the four groups of radiomics features with LN status was assessed by using a Mann-Whitney U test. The area under curves (AUC) of the receiver operating characteristic curves (ROC) were compared with data obtained from the conventional CT image.

results:

The 3D HU gradient map showed a great power of distinguishing among different components and was considered as a more effective tool for revealing the intratumour heterogeneity than the conventional CT image since the slope of spectral HU curves were significantly higher in malignant tumor. More than 500 radiomics features extracted from the regions of LN during the AP and the PVP exhibited significant differences (P <0.05). Moreover, the numbers of this kind of features extracted from the regions of BC were more than 200. The highest AUC of single feature was 0.70, which was higher than those from the conventional CT image.

Conclusion:

Quantitative radiomics features based on 3D HU gradient maps have the potential to be exploited as an effective biomarker for preoperative prediction of lymph node metastasis in breast cancer.

Citation Format: Dong D, Zhang X, Fang M, Shen J, Tian J. Spectral CT based radiomics signature: A potential biomarker for preoperative prediction of lymph node metastasis in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-38.
Abstract P2-06-04: Breast cancer after Hodgkin lymphoma: Influence of endogenous and exogenous gonadal hormones on the radiation dose-response relationship
Authors: Krul IM , Opstal - van Winden AWJ , Aleman BMP , Janus CPM , van Eggermond AM , de Bruin ML , Hauptmann M , Krol ADG , Schaapveld M , Broeks A , Kooijman KR , Fase S , Lybeert ML , Zijlstra JM , van der Maazen RWM , Kesminiene A , Diallo I , de Vathaire F , Russell NS , van Leeuwen FE
Published: March 2017

Background

After chest radiotherapy (RT) for Hodgkin lymphoma (HL), women experience a dose-dependent increased breast cancer (BC) risk. It is unknown whether endogenous and exogenous gonadal hormones affect the radiation dose-response relationship.

Methods

We conducted a nested case-control study among female 5-year HL survivors treated before 41 years between 1965-2000. Data were collected through medical records and questionnaires for 174 BC cases and 466 matched controls. RT charts, simulation films and mammography reports were used to estimate the radiation dose to the location of the breast tumor.

Results

The median interval between HL and BC diagnosis was 21.9 years. 98% of BC cases had received chest RT, compared to 92% of controls. We observed a linear radiation dose-response curve with an adjusted excess odd ratio (EOR) of 5.4%/Gray (95%CI:1.8%-13.37%). Women with menopause <30 years (caused by high-dose procarbazine or pelvic RT) had a lower BC risk (OR:0.13, 95%CI:0.03-0.54) than women with menopause ≥50 years. BC risk increased with 7.4% for each additional year of intact ovarian function after RT (P<0.001). Among women with an early menopause (<45 years), the use of hormone replacement therapy (HRT) for ≥2 years did not increase BC risk (OR:0.81, 95%CI:0.30-2.21). Endogenous and exogenous hormones did not statistically significantly modify the slope of the radiation dose-response relationship.

Conclusion

HRT use did not appear to increase BC risk in female HL survivors with a therapy-induced early menopause. Moreover, there was no evidence for interaction between RT dose and years with intact ovarian function or HRT use.

Citation Format: Krul IM, Opstal - van Winden AWJ, Aleman BMP, Janus CPM, van Eggermond AM, de Bruin ML, Hauptmann M, Krol ADG, Schaapveld M, Broeks A, Kooijman KR, Fase S, Lybeert ML, Zijlstra JM, van der Maazen RWM, Kesminiene A, Diallo I, de Vathaire F, Russell NS, van Leeuwen FE. Breast cancer after Hodgkin lymphoma: Influence of endogenous and exogenous gonadal hormones on the radiation dose-response relationship [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-06-04.
Abstract P2-07-12: The association between patient comorbidity and breast cancer survival
Authors: Han J , Lee H-B , Lee E-S , Kang YJ , Kim Y , Choi J , Rhu J , Han W , Noh D-Y , Moon H-G
Published: March 2017

Background

There are studies suggesting significant association between the patient's comorbidity and perioperative outcomes. In breast cancer, patient comorbidity can also influence the oncologic outcome by affecting the decisions regarding adjuvant treatments. In this study, we examined the long-term oncologic outcome in breast cancer patients who underwent curative surgery according to their pre-existing comorbid conditions.

Methods

The medical records of 2,501 patients who underwent surgery for primary breast cancer from June 2006 to June 2010 were reviewed retrospectively. The patients were classified into three groups (ASA 1, 2, 3) according to preoperative ASA status determined by the anesthesiologists. Clinico-pathologic characteristics and survival outcomes of the patients were compared among the different co-morbidity groups.

Result

There were 1,792 (71.6%), 665 (26.6%), and 44 (1.8%) patients in ASA 1, 2, and 3, respectively. Total 95 (3.8%) deaths and 269 (10.8%) recurrences (loco-regional and distant) occurred during the median follow-up period of 71 months. Patients with high comorbidity showed significantly higher rate of death (51 (2.8%), 38 (5.7%) and 6 (13.6%) deaths in ASA 1, 2 and 3 group, respectively, p<0.001). The ASA 3 patients also showed significantly higher rate of breast cancer recurrence when compared to other groups (180 (10.0%), 80 (12.0%) and 9 (20.5%) in ASA 1, 2 and 3, respectively, p=0.041). Cox multivariate analysis demonstrated that high ASA score (ASA 3) was an independent prognostic factor in DFS, OS and BCSS (95% confidence interval [CI], 1.661-6.780; p=0.001, 1.753-11.321; p=0.002 and 2.222-18.429; p=0.001). Fewer patients in the high co-morbidity group received adjuvant therapies (77 (4.3%), 44 (6.6%) and 8 (18.2%) in ASA 1, 2 and 3, p<0.001). The increased recurrence of breast cancer in the high morbidity group was most seen in patients who did not receive adjuvant therapies. The incidence of serious adverse effect during the adjuvant therapy did not differ according to the co-morbidity conditions.

Conclusion

In this study, high comorbidity was related to increased risk of death and recurrence in breast cancer. The increased risk of recurrence in high co-morbidity group was mostly seen in patients who did not receive adjuvant therapies. In patients who underwent the adjuvant therapies, the incidence of serious adverse effects did not differ according to the co-morbidity status.

Citation Format: Han J, Lee H-B, Lee E-S, Kang YJ, Kim Y, Choi J, Rhu J, Han W, Noh D-Y, Moon H-G. The association between patient comorbidity and breast cancer survival [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-07-12.
Abstract P3-03-08: A large-scale functional screen to identify resistance mechanisms to selective estrogen receptor degraders fulvestrant and GDC-810 in ER+ breast cancer
Authors: Mao P , Quartey Q , Cohen O , Piccioni F , Wagle N
Published: March 2017

Therapies that target the estrogen receptor provide clinical benefit and improved survival for patients with estrogen receptor-positive (ER+) breast cancer, yet drug resistance remains a challenging problem, leading to disease relapse and mortality. In recent years, the selective estrogen receptor degrader (SERD) fulvestrant has become an important therapeutic option for patients with resistant ER+ metastatic breast cancer, and newer oral SERDs such as GDC-810 are currently being tested in clinical trials. The mechanisms of intrinsic and acquired resistance to SERDs remain to be fully elucidated.

We conducted a large-scale lentiviral open reading frame (ORF) screen to identify genes whose overexpression confers drug resistance to either fulvestrant or GDC-810 in the ER+ breast cancer cell line T47D. The lentivral ORF expression library used in this study consists of 16,544 barcoded ORFs, including 2,767 ORFs with mutations. The initial screen yielded 72 genes resulting in resistance to fulvestrant and 85 genes resulting in resistance to GDC-0810, with 44 genes overlapping. The top ranked-genes included multiple genes belonging to the PI3K/Akt, ERbB/HER, and FGF/FGFR pathways as well as genes involved in cell cycle progression.

Fibroblast growth factor receptor 1 (FGFR1) amplifications are frequently observed in patients with ER+ breast cancer, and have previously been implicated in resistance to endocrine therapies. Several FGFs (FGF3, FGF6, FGF10, and FGF22) were among the top-ranked resistance genes for both fulvestrant and GDC-0810, suggesting that activation of the FGFR signaling pathway may render cells resistant to fulvestrant and GDC-810. In the presence of FGF2, overexpression of FGFR1 in ER+ breast cancer cells resulted in resistance to both fulvestrant and GDC-0810. The ability of an FGFR inhibitor to overcome FGFR-mediated resistance to SERDs is being tested. Additional potential resistance genes identified in the ORF screen are also being validated.

In summary, a whole-genome functional resistance screen has identified several candidate genes and pathways that may cause resistance to fulvestrant and GDC-810. Several of these candidates, such as FGFR1, are also found in patients who develop resistance to SERDs, suggesting rational combination therapies to overcome or preempt SERD resistance.

Citation Format: Mao P, Quartey Q, Cohen O, Piccioni F, Wagle N. A large-scale functional screen to identify resistance mechanisms to selective estrogen receptor degraders fulvestrant and GDC-810 in ER+ breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-03-08.
Abstract P3-03-10: Penfluridol reduces paclitaxel resistance in breast cancer by inhibiting HER2/β-catenin signaling
Authors: Gupta N , Gupta P , Srivastava S
Published: March 2017

This abstract was not presented at the symposium.
Abstract P3-04-03: S100β as a predictive biomarker and monitoring tool in endocrine resistant breast cancer
Authors: Charmsaz S , Hughes É , Byrne C , Bane F , Tibbitts P , McIlroy M , Hill AD , Young LS
Published: March 2017

In estrogen receptor positive breast cancer, endocrine therapy is the standard line of treatment and even though it results in reduced recurrence and mortality, a significant number of patients will eventually relapse. Early detection of metastatic disease would significantly enhance management of endocrine resistant breast cancer. Here we investigate the potential of the calcium-binding protein S100β as a predictive biomarker and monitoring tool in endocrine treated patients. Furthermore, the efficacy of S100β inhibition as therapy in patients that fail first line endocrine therapy was examined.

Primary tumor tissue expression of S100β protein was assessed in a retrospective cohort of endocrine treated breast cancer patients. Expression of S100β indicated a significant reduction in time to disease recurrence (n=509, Wilcoxon p<0.0001, hazard ratio 2.43, 95% C.I. is 1.607 to 3.69, p<0.0001, Cox proportional hazard model).

S100β protein is also detectable in serum of breast cancer patients and elevated levels of serum S100β prior to removal of primary tumor is associated with poor disease free survival in endocrine treated patients (n=190, Wilcoxon p=0.0367, hazard ratio 2.68, 95% C.I. is 1.12 to 6.41, p=0.026, Cox proportional hazard model). Serum levels of S100β are significantly reduced after primary tumor resection (n=19, p=0.0003). In serial samples taken during the treatment period, elevated levels of S100β significantly associated with disease progression and with the emergence of metastatic disease (p=0.0031).

In an in-vivo model of endocrine resistant breast cancer, raised levels of S100β marked the emergence of disease progression. The oncogene steroid receptor co-activator 1 (SRC1) and its interaction with homeobox protein (HOXC11) regulates S100β production in a src-kinase dependent manner. Here, src-kinase inhibition reduced tumor burden with a concomitant reduction in serum S100β. We also observed a marked reduction in expression of proliferative marker Ki67 and S100β protein following the treatment of endocrine resistant patient tumor explants with src-kinase inhibitor.

Associations between elevated levels of serum S100β and subsequent disease progression in endocrine treated patients, suggests S100β as a monitoring tool for early detection of disease progression. Additionally high level of S100β can be used as a potential companion diagnostic tool for stratifying patients on endocrine therapy suitable for treatment with small molecule src-kinase inhibitor.

Citation Format: Charmsaz S, Hughes É, Byrne C, Bane F, Tibbitts P, McIlroy M, Hill AD, Young LS. S100β as a predictive biomarker and monitoring tool in endocrine resistant breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-03.
Abstract P3-04-08: The role of HER2 mutations in resistance to endocrine therapy in ER+ breast cancer
Authors: Nayar U , Cohen O , Oh C , Wagle N
Published: March 2017

Resistance to endocrine therapies in estrogen receptor positive (ER+) metastatic breast cancer is widespread, and understanding the mechanisms whereby these tumors acquire resistance is a critical need. Through whole-exome sequencing of metastatic tumor biopsies from patients with endocrine resistant ER+ metastatic breast cancer, we identified 13 different HER2 mutations, including five in the kinase domain, four in the signaling domain, three in the extracellular domain, and one in the transmembrane region of the protein. Two of the kinase domain mutations (L755S and V777L) have been previously described and shown to be activating and resistant to reversible anti-HER2 targeted therapies; the remaining mutations have not been reported. In several of these patients, whole exome sequencing of a pre-treatment primary tumor did not identify the HER2 mutations seen in the corresponding metastatic tumor, suggesting that they were acquired during therapy. To examine the role of HER2 mutations in endocrine resistance, we generated ER+ breast cancer cell lines (MCF7 and T47D) stably expressing the HER2 mutants observed in our clinical data. Several mutants promoted enhanced growth in charcoal dextran-stripped media, which lacks estradiol and mimics treatment with aromatase inhibitor. In addition, several mutants conferred varying degrees of resistance to fulvestrant and tamoxifen. Taken together, these results suggest that HER2 mutations are associated with acquired resistance to endocrine therapies in patients with ER+ breast cancer. The ability of irreversible anti-HER2 agents as well as other agents that target the HER2 pathway to overcome this resistance is being tested for individual HER2 mutations in vitro. The results from these studies may provide a clinical rationale for therapeutic combination strategies in patients with refractory tumors that have acquired endocrine resistance through HER2 mutations.

Citation Format: Nayar U, Cohen O, Oh C, Wagle N. The role of HER2 mutations in resistance to endocrine therapy in ER+ breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-08.
Abstract P3-04-10: Utility of the orally bioavailable selective estrogen receptor degrader AZD9496 in ESR1 mutant preclinical models of estrogen receptor positive breast cancer
Authors: Morrow CJ , Lawson M , Ladd B , de Almeida C , James N , Curwen JO , Hanson L , Bell K , Goeppert A , Fisher D , Gangl E , De Savi C , Scott JS , D'Cruz C , Klinowska T , Weir HM
Published: March 2017

Approximately 70% of breast cancers express estrogen receptor alpha (ERα) and anti-hormonal therapies which either block the production of estrogen (e.g. anastrozole) or directly block ERα function (e.g. tamoxifen) remain the mainstay of treatment for these patients. While these therapies are highly effective resistance can occur. A common resistance mechanism to anti-hormonal agents is the mutation of ESR1, the gene that encodes ERα, which leads to ligand independent activity. Evidence is emerging that the selective estrogen receptor degrader (SERD) fulvestrant is effective in patients with ESR1 mutations. However, given the low bioavailability of fulvestrant and the still detectable levels of ER in clinical samples after treatment with fulvestrant it is hypothesised that SERDs with improved pharmacokinetic properties which are able to drive greater degradation of ERα may provide additional clinical benefit. We have previously described the discovery and characterisation of the orally bioavailable SERD AZD9496, which is currently in phase I clinical trials in ER+ breast cancer patients. Here we report the preclinical activity of AZD9496 in cell line and patient derived xenograft models expressing clinically relevant ESR1 mutations. We have engineered MCF-7 cells to express Y537S ESR1 which confers the ability to proliferate in the absence of estradiol, consistent with ligand independent activation of ER signalling. AZD9496 is able to inhibit proliferation of these cells and downregulate progesterone receptor protein expression at low nanomolar concentrations. Furthermore, when MCF-7 Y537S ESR1 cells are implanted as xenografts they grow in the absence of exogenous estradiol, are as sensitive to AZD9496 as parental MCF7 xenografts and demonstrate downregulation of ER dependent biomarkers. AZD9496 also has anti-tumour and pharmacodynamic efficacy in patient derived xenograft models expressing D538G ESR1. Taken together, these data strengthen the body of data suggesting that SERDs may be active in patients with tumours containing ESR1 mutations and supports the inclusion of this patient population in AZD9496 clinical trials.

Citation Format: Morrow CJ, Lawson M, Ladd B, de Almeida C, James N, Curwen JO, Hanson L, Bell K, Goeppert A, Fisher D, Gangl E, De Savi C, Scott JS, D'Cruz C, Klinowska T, Weir HM. Utility of the orally bioavailable selective estrogen receptor degrader AZD9496 in ESR1 mutant preclinical models of estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-10.
Abstract P3-04-19: Inhibition of ER-positive breast cancer progression with duavee, a new form of hormone replacement therapy
Authors: Dembo AG , Aledort E , Greene GL
Published: March 2017

Menopause occurs in all women between the ages of 45 and 55 and often results in undesirable vasomotor symptoms. Hormone replacement therapy (HRT) can alleviate these symptoms, including hot flashes, difficulty sleeping, fatigue, and vaginal atrophy, and also prevents osteoporosis. PremPro, a HRT formulation that combines conjugated equine estrogens (CE) with medroxyprogesterone acetate, was found to increase the risk of breast cancer in the Women's Health Initiative (WHI) trial. Due to the perceived risk based largely on the results of the WHI trial, the number of women taking HRT has dramatically decreased. Studies suggest that breast cancer cases from PremPro treatment were primarily due to the outgrowth of occult tumors, not the formation of new disease. Duavee, a new form of HRT that combines CE and bazedoxifene (BZA), a selective estrogen receptor modulator (SERM) and degrader (SERD), has been approved by the FDA for treatment of moderate to severe hot flashes and to reduce the risk of osteoporosis. Importantly, this CE+BZA mixture not only relieves symptoms associated with menopause, but it also does not stimulate the breast or uterus. Several preclinical studies suggest that CE+BZA might be protective in the breast, however the mechanism of action of this new combination therapy is not known. Our goal, therefore, is to elucidate the underlying molecular mechanisms by which CE+BZA differentially affects estrogen receptor alpha (ERα) action in the mammary gland, using transcriptome and whole genome occupancy analysis in breast cancer cell lines. We are also studying the effects of CE+BZA on early mammary cancer progression in the polyoma middle T antigen (PyMT) transgenic mouse model, which is sensitive to estrogens. In addition, we are studying the effects of CE+BZA in an ERa-positive patient-derived xenograft (PDX) mouse model. We have determined that CE modulates gene expression in MCF7 cells similar to 17β-estradiol (E2), and that BZA is able to inhibit these effects. We have also observed that CE increases ERα occupancy, similar to E2, at response elements associated with some estrogen target genes, whereas CE+BZA decreases this occupancy. In the PyMT mouse model, CE+BZA delays the onset of mammary tumors in ovariectomized mice and prolongs their survival when compared to E2 and CE treatment alone. In the PDX model, the CE+BZA tumor growth curve is below vehicle, although it does not quite reach statistical significance. An improved understanding of the molecular mechanisms of CE+BZA action in hormone sensitive breast cancer cell and animal models should have important implications for women considering HRT.

Citation Format: Dembo AG, Aledort E, Greene GL. Inhibition of ER-positive breast cancer progression with duavee, a new form of hormone replacement therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-19.
Abstract P3-04-21: Androgen receptor in tamoxifen-resistant breast cancer is affected by SUMO
Authors: Bahnassy S , Kumar S , Ren J , Frutiz G , Karami S , Bawa-Khalfe T
Published: March 2017

Resistance to tamoxifen is a major problem in treating women with estrogen receptor-positive (ERa+) breast cancer (BCa). Previous studies report elevated levels of the androgen receptor (AR) in tamoxifen-resistant (TamR) human mammary tumors. Inversely, in vitro overexpression of AR in ERa+-MCF-7 cells potentiates growth in the presence of tamoxifen. AR is a target for small ubiquitin like modifiers (SUMO) posttranslational modification (PTM). Prostate cancer (PCa) studies, show that SUMO-PTMs can have diverse effects on AR transcriptional activity, by modifying the AR itself or its co-regulators. SUMOylation regulates the AR's interaction with chromatin and modulates its function in a gene selective manner. Although SUMO-1 inhibited the AR transcriptional activity, SUMO-3 strongly enhanced the transactivation of AR in LNCaP cells but negatively affected the AR transcriptional activity in primary prostate epithelial cells. On the other hand, SUMO modifications and its subsequent effects on the AR in breast tumors and in particular TamR-BCa is unknown. Our objective is to understand how SUMO-PTMs affect AR activity in TamR-BCa. Others report that high Ubc9, a SUMO E2 conjugating enzyme, correlates with with aggressive phenotypes of BCa and that PIAS3, a SUMO E3 ligase, expression increases in breast tumors. Consistently, we now report that global SUMO2/3-conjugation is enhanced while the full-length SUMO protease SENP7 (SENP7L) is reduced in TamR-BCa cells. Collectively, these observations would suggest reduced SUMO dynamics in TamR-BCa as compared to tamoxifen-sensitive (TamS) BCa cells. Unlike PCa cells that favor unmodified over SUMOylated AR, we report that AR SUMOylation is potentiated in TamR-BCa cells. Functionally, SUMOylation of AR augments its chromatin binding and enhances its transcriptional activity. Our results suggest that the level of unmodified to SUMOylated AR is dramatically altered with onset of TamR and drives a functionally distinct population of AR in TamR versus TamS BCa. Consistently these biochemical reactions that define protein diversity could have a major impact on drug resistance in BCa.

Citation Format: Bahnassy S, Kumar S, Ren J, Frutiz G, Karami S, Bawa-Khalfe T. Androgen receptor in tamoxifen-resistant breast cancer is affected by SUMO [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-21.
Abstract P3-04-24: Identification of preclinical mechanisms driving acquired resistance to selective ERa degraders (SERDs), CDK4/6 inhibitors, or to combinations of both agents
Authors: O'Brien T , Xiao Y , Ong C , Daemen A , Friedman L
Published: March 2017

Estrogen positive (ER+) breast cancer accounts for the majority of all breast cancers and standard practice is treatment with endocrine therapy. Recently a series of CDK4/6 inhibitors have emerged that can be effectively combined with estrogen modulators to treat ER+ breast cancer patients. The most advanced of these compounds, palbociclib, is now approved in the US in combination with letrozole or fulvestrant. Even though these combinations are effective, invariably patients will relapse. Our understanding of the mechanisms of acquired resistance to CDK4/6 inhibitors is still relatively nascent, and it is not known whether acquired resistance to combination treatments (e.g. palbociclib with fulvestrant) will be the same as mechanisms for the individual single agents. Additionally, it is not known if tumors that no longer respond to one combination regimen will remain sensitive to other standard of care treatments.

To pre-clinically address these questions we generated cell lines that have acquired resistance to three Selective Estrogen Receptor Degraders (SERDs) and to two CDK4/6 inhibitors, palbociclib and abemaciclib. Additionally, we also generated cells with acquired resistance to the combination of fulvestrant and palbociclib. Characterization of cells resistant to each of these treatments will be presented. Initial data indicate that MCF7 cells with acquired resistance to SERDs have increased PI3K signaling and MEK/ERK signaling and have increased sensitivity to inhibitors of these pathways when treated with single agents. These cells are also more sensitive to palbociclib relative to parental cells. All 11 clones with acquired resistance to abemaciclib lose Retinoblastoma (Rb) expression and 20/24 palbociclib-resistant clones lose Rb expression, indicating the importance of Rb to CDK4/6 inhibitor activity. Interestingly, palbociclib resistant clones have decreased sensitivity to fulvestrant and to PI3K inhibitors, and investigation is under way to determine if that relates to slower doubling times for the clones.

Detailed characterization of resistant clones reveals a surprisingly complex interaction between ERa and CDK4/6 signaling, and further results, including acquired resistance to drug combinations, will be presented. These preclinical studies may inform biomarkers of sensitivity and resistance to endocrine agents and CDK4/6 inhibitors.

Citation Format: O'Brien T, Xiao Y, Ong C, Daemen A, Friedman L. Identification of preclinical mechanisms driving acquired resistance to selective ERa degraders (SERDs), CDK4/6 inhibitors, or to combinations of both agents [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-24.
Abstract P3-05-09: Glucocorticoid receptor modulation affects ER+ breast cancer cell proliferation
Authors: Tonsing-Carter E , Bowie KR , West DC , Harkless RV , Hernandez KM , Conzen SD
Published: March 2017

Early-stage ER+ breast cancer with high tumor glucocorticoid receptor (GR) expression is associated with improved long term relapse-free survival compared to tumors with low GR expression. In addition, activation of GR inhibits estradiol-mediated ER+ BC cell proliferation. This finding led us to hypothesize that GR and ER engage in nuclear receptor cross-talk to affect pro-proliferative gene expression, thus contributing to a better outcome in ER+/GR+ BC patients. To better understand the mechanisms by which ER/GR co-activation contributes to this more indolent phenotype, we performed ChIP-sequencing and gene expression analyses in ER+/GR+ BC cell lines (MCF-7 and T47D).

We found that co-activation of ER and GR led to decreased ER+ BC cell proliferation in vitro. Furthermore, following co-activation of ER/GR, there was decreased gene expression of key cell cycle genes (e.g. CDK6, CDK2 and CCNE1) compared to ER-activation alone. Studies are underway to determine if this decrease in gene expression is associated with less CDK activity as well as a slowing of cell cycle progression.

We also wanted to know if GR activation with a pure agonist versus a mixed GR modulator was required for decreasing ER-mediated cell proliferation. Based on our previous work (DC West et al. MCR 2016), we hypothesized that ligand-mediated GR activation could be working by preventing access of ER to regulatory regions of pro-proliferative genes rather than causing direct GR agonist-mediated gene expression. To examine this question, we used a GR modulator, mifepristone (expected to alter ER-mediated gene expression indirectly). Indeed we found that a GR modulator also reduced ER-mediated cell proliferation. We are currently testing the mechanisms by which GR modulators affect estradiol-mediated cell cycle gene expression.

Taken together, these studies suggest that modulation of GR activity could be an effective approach to decrease ER+ tumor cell proliferation. Xenograft studies are underway to examine whether the addition of GR modulation to tamoxifen will improve tumor shrinkage compared to tamoxifen alone.

Citation Format: Tonsing-Carter E, Bowie KR, West DC, Harkless RV, Hernandez KM, Conzen SD. Glucocorticoid receptor modulation affects ER+ breast cancer cell proliferation [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-05-09.