Hormone Receptor-positive Breast Cancer Patients Research Articles

Super-ARMS: A new method for plasma ESR1 mutation detection

BackgroundESR1 mutation is an important mechanism of drug resistance and recurrence in hormone receptor-positive breast cancer patients during AI treatment. Patient could still benefit from treatment with fulvestrant after ESR1 mutated. ObjectiveAt present, there is still no suitable method to detect ESR1 mutation in plasma as clinical promotion method. We aim to improve from ARMS-PCR to get a method with higher sensitivity but no additional cost is incurred. MethodsWe designed new primers for ESR1. Then positive and negative standard sample was used for sensitivity and specificity tests. Lastly, we collected patient peripheral blood sample and analyzed the performance of Super-ARMS in plasma ctDNA samples. ResultsA total of 207 patients were enrolled in this study, including 142 prime breast cancer (PBC) patients and 65 metastasis breast cancer(MBC) patients. The mutation rate was as high as 27.9%(12/43) in MBC patients with AI treatment. But only 2.97%(3/101) in PBC patients with AI and 0% in both MBC or PBC patient without AI. There was no significant difference in Super-ARMS results compared with DDPCR method. ConclusionSuper-ARMS is a method that has sensitivity close to DDPCR and has the convenience and low price of ARMS-PCR for plasma ctDNA ESR1 mutation detection. It has obvious advantages compared with other method such NGS and DDPCR as clinical promotion method.

A validated model to predict low recurrence risk distinguished by 21-gene recurrence score in hormone receptor-positive invasive breast cancer patients.

532 Background: In the prospective TAILORx and RxPONDER trials, the 21-gene Recurrence Score (RS) showed endocrine therapy alone was non-inferior to chemo-endocrine therapy in the analysis of invasive disease-free survival in postmenopausal hormone-receptor (HR)-positive breast cancer patients with RS < = 25. They also indicated chemotherapy was associated with benefit for women 50 years or younger with RS 11 to 25. However, in Japan, the test is not conventionally available because of non-coverage by national insurance. We aimed to develop and validate a model to predict RS using clinicopathological factors that identify patients who would have low risk shown by testing the 21-gene RS and can avoid chemotherapy. Methods: Four hundred patients, including 187 N0/1 postmenopausal, and 213 N0 premenopausal women who underwent surgery and had the RS from St. Luke’s International Hospital, Tokyo, Japan, were included in derivation cohort. Derivation cohort was divided into 2 groups by RS 25; patients with RS of 0 to 25 (n = 321) and with RS over 26 (n = 79). Multivariate logistic regression analysis was performed using candidate factors for all patients and pre- or postmenopausal patients. The prediction model was validated using an external cohort of 70 patients from Showa University School of Medicine, Tokyo, Japan. Results: Nuclear grade (NG) (adjusted OR, 5.28, 95% CI, 2.47–11.30), high Progesterone receptor (PgR) expression (Allred score 7-8) (adjusted OR, 10.62, 95% CI, 5.34–21.13) and low Ki67 level ( < = 20%) (adjusted OR, 5.29, 95% CI, 2.33-12.01) were significant independent predictors of RS of 0 to 25. With these factors could predict RS of 0 to 25 (AUC of 0.848, 95% CI, 0.803-0.893) with the highest probability of low-RS for 100%. The prediction model of the validation cohort had same discriminatory ability having an AUC of 0.812 (95% CI, 0.701-0.923). In postmenopausal patients, NG (adjusted OR, 4.81, 95% CI, 1.72–13.42), high PgR expression (adjusted OR, 10.62, 95% CI, 4.52–37.72), and low Ki67 level (adjusted OR, 4.94, 95%CI, 1.87-13.04) were significantly associated with RS of 0 to 25 in multivariate analysis. A regression model with these 4 factors could predict RS of 0 to 25 (AUC of 0.842, 95%CI, 0.782-0.902). In premenopausal patients, NG (adjusted OR, 8.76, 95% CI, 1.14–67.40), high PgR expression (adjusted OR, 3.22, 95% CI, 1.61–6.43), and low Ki67 level (adjusted OR, 2.87, 95% CI, 1.20–6.87) were significantly associated with RS of 0 to 10 in multivariate analysis. These factors could predict RS of 0 to 10 (AUC of 0.811, 95% CI, 0.731-0.891). However, the highest probability of low-RS provided this model for premenopausal women was 46.8%. Conclusions: Our validated model could provide useful information to distinguish low-RS especially for postmenopausal patients with high reproducibility. However, for premenopausal women, the 21-gene RS is warranted.

Breast Cancer Index and prediction of benefit from extended endocrine therapy based on treatment compliance: An IDEAL study.

531 Background: The IDEAL trial randomized hormone receptor-positive (HR+) breast cancer patients to 5 vs 2.5y of extended letrozole after completion of 5y of adjuvant endocrine therapy. In the parent trial, approximately 60% of patients overall were compliant with endocrine treatment (59% vs 74% compliance in 5y and 2.5y arms, respectively), with patient experiences as the most significant factors leading to treatment discontinuation. Breast Cancer Index is a gene expression-based signature that predicts which HR+ patients are likely to benefit from extended endocrine therapy (EET) vs those unlikely to benefit [BCI (H/I)-High and -Low, respectively]. The current study examined EET compliance and outcome by BCI (H/I) status in patients treated in the IDEAL trial. Methods: Patients with available primary tumor specimens were eligible for this blinded study. Primary endpoint was recurrence-free interval (RFI), including locoregional and distant recurrences. Kaplan-Meier and Cox proportional hazards regression analysis were used to analyze the benefit of EET. Non-compliance was defined as completion of ≤60% of treatment duration (≤3y for 5y arm; ≤1.5y for 2.5y arm) for any reason other than disease events. Overtreatment was defined as % compliant BCI (H/I)-Low patients in the 5y arm; undertreatment was % noncompliant BCI (H/I)-High patients in the 5y arm. Results: 908 HR+ patients (73% pN+, 59y, 45% pT1, 48% pT2) were included. 78% (n = 708) of patients were compliant, of which 48% (n = 338) were BCI (H/I)-High and 52% (n = 370) were BCI (H/I)-Low. In non-compliant patients (22%, n = 200), 45% (n = 91) were BCI (H/I)-High and 55% (n = 109) were BCI (H/I)-Low. BCI (H/I)-Low patients irrespective of compliance status did not derive significant benefit from EET (P = 0.922, compliant subset; 0.894 non-compliant subset). Compliant BCI (H/I)-High patients showed significant benefit from EET (HR 0.35, 95% CI 0.16-0.79; absolute benefit 11.7%; P = 0.008) whereas non-compliant BCI (H/I)-High patients did not (HR 0.75, 95% CI 0.17-3.35; absolute benefit 2.1%, P = 0.704). In this study, 38% of patients in the 5y EET arm were BCI (H/I)-Low and compliant and thus were overtreated, while 13% of patients in the 5y EET arm were BCI (H/I)-High and non-compliant and thus were undertreated. Conclusions: Patients that were BCI (H/I)-Low did not derive significant benefit from 5 vs 2.5y of EET even when compliant, and thus may be considered for treatment de-escalation. Importantly, BCI (H/I)-High patients with endocrine responsive disease showed significant improvements in outcome when compliant and should be guided to continue treatment. BCI may serve as an important genomic tool to increase EET compliance and identify patients that may be candidates for increased side effect management and support to potentially improve outcomes. Clinical trial information: NTR3077; BOOG 2006-05; Eudra-CT 2006-003958-16.

Comparing practice patterns and outcomes for early-stage hormone receptor-positive and node-positive breast cancer patients with high-intermediate-risk Oncotype Dx scores in the National Cancer Database.

e12520 Background: Oncotype Dx (ODX) is a commercial diagnostic test primarily used to predict the likely benefit from chemotherapy in ER+, HER2-, and node negative breast cancer. The prognostic value (recurrence risk) has also been demonstrated to apply to early stage lymph node positive (LN+) disease in a number of retrospective and prospective studies. The ongoing RxPONDER trial aims to clarify the predictive value of RS in LN+ population. In light of the initial results, we analyzed the practice patterns and outcomes for HR+/Her2 -/node positive breast cancer patients receiving ODX testing in the years from 2010-2017 with RS 14-25 in a retrospective observational study of the NCDB. Methods: Women with HR+/Her2 -/node positive breast cancer receiving ODX testing from 2010-2017 were identified in the NCDB using TAILORx and RxPONDER patients’ inclusion criteria: ages 18-75, 6-50mm invasive tumors, N1, M0, ER+/HER2 -. The impact of ODX results in the high-intermediate range (14-25) and other clinico-pathologic variables on the receipt of chemotherapy were compared. Additionally, we examined the impact of chemotherapy on overall survival (OS). Frequencies, Kaplain-Meier analysis, and changepoint analysis using the Contal and O’Quigley method were utilized. Results: There were 109,652 T1-2 and N1 patients of whom 32,506 (29.6%) received ODX testing. 13,461 (41.4%%) women had scores in the high-intermediate (14-25) range. The majority tended to have only 1 LN involved (1LN: 77.2%, 2LNs: 17.5%, 3LNs: 5.3%), had a mean age of 57.8y, were Caucasian (86.4%), and were preferentially tested at academic or comprehensive community cancer programs (79.2%). 6,610 (49.3%) patients were recommended chemotherapy, the median ODX score for all women who were recommended chemotherapy was 20 compared to 17 for those whom chemotherapy was not recommended. 5,068 (76.7%) women had documentation of receiving chemotherapy which correlated with improved OS regardless of age. Conclusions: In the group of women with HR+/Her2 -/node positive breast cancer, clinicians appear to utilize ODX testing in less than one-third of patients, possibly finding RS to be most useful in guiding adjuvant therapy recommendations when only 1LN is involved. Both the recommendation and receipt of chemotherapy correlated linearly with increasing RS, as expected based on the current NCCN guideline recommendations. We identified an OS benefit when chemotherapy was administered, regardless of patient age. Long-term follow-up in the RxPONDER trial will likely continue to clarify the predictive value of RS < 25 in the ER+/HER2-/node positive breast cancer population.

Prognostic value of p53 expression in hormone receptor-positive and human epidermal growth factor receptor 2-negative breast cancer patients receiving neoadjuvant chemotherapy.

The aim of this study was to determine whether the outcome to neoadjuvant chemotherapy (NAC) can be predicted by analyzing p53 expression in hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer patients. We retrospectively reviewed 594 patients diagnosed with stage I-III HR-positive, HER2-negative breast cancer, and treated with NAC at the Asan Medical Center between 2008 and 2014. Expression of p53 was assessed, and overall survival (OS) and breast cancer-specific survival (BCSS) were investigated and compared between groups. At a median follow-up period of 69.8months, OS and BCSS were higher in the p53-negative (p53(-)) group than in the p53-positive (p53(+)) group. Five-year OS was 95.4% in the p53(-) and 92.1% in the p53(+) group (p = 0.005). BCSS was 96.2% in the p53(-) group and 93% in the p53(+) group (p = 0.008). High expression of immunohistochemically detected p53 was strongly and significantly associated with decreased OS and BCSS than low p53 expression, suggesting that p53 may be a powerful prognostic factor in HR-positive, HER2-negative breast cancer patients receiving NAC.

Abstract PS9-71: The effect of using adjuvant aromatase inhibitors on cognitive functions in postmenopausal women with hormone receptor-positive breast cancer

Abstract Background:Aromatase inhibitors (AIs) are used for the adjuvant treatment of early breast cancer. Although generally well-tolerated, they have some adverse effects. Because of AIs are used long term in adjuvant treatment, side effects are also very important. Preclinical and a little clinic data indicate that estrogens exert neurotrophic and neuroprotective actions in the brain. So estrogen appears to play an important role in cognitive function and memory. We know that AIs reduce circulating estrogen to very low levels. For this reason, there has been concern that these agents may have a negative effect on cognitive functions. However, this situation is still unclear. The purpose of our study is to evaluate the relationship between duration of treatment and cognitive functions in patients with breast cancer who use AIs in adjuvant therapy. Methods:Patients diagnosed with breast cancer who use AIs as adjuvant treatment and followed up at the Akdeniz University Medical Oncology Clinic were included. The patients were surveyed for demographic characteristics. Montreal Cognitive Assessment (MoCA) and Standardized Mini-Mental State Examination (SMMT) tests were applied to patients by the same investigator to evaluate their cognitive functions. The total scores of the tests and the orientation, naming, short-time memory, visuospatial functions-executive functions, attention, abstract thinking, language which are the MoCA subscales were evaluated separately. In the Turkish population, the normal range of the MoCA and SMMT tests are 21-30 points and 24-30 points, respectively. Patients were grouped as 0-6, 6-12, 12-24, 24-36, 36 and more months according to the duration of AIs using time. 200 patient’s data were analyzed with SPSS package program. This study was approved by the Akdeniz University Faculty of Medicine Clinical Research Ethnics Committee and was conducted in accordance with declaration of Helsinki. Results:The median follow-up time was 55.5 months. The median duration of AIs treatment was 36.5 months. The mean age of patients was 61.3 years-old. There was no relationship between duration of treatment and MoCA and SMMT scores which indicates cognitive functions (p>0.05). In addition, no statistically relationship was found in the evaluation of MoCA subscales (p>0.05). As expected, the total MoCA and SMMT scores were affected by factors such as age, education level, and employment status. Interestingly, although it was not our main purpose, a causal relationship between the presence of hypertension and cognitive decline was shown in our study (p: 0.004). A statistically strong correlation was found between the MoCA and SMMT scores. So, our data are reliable. The duration of treatment with AIs and MoCA and SMMT scores of the patients were given in Table 1. Conclusions:As a result, despite conflicting results in the literature, we showed with 200 patients that adjuvant treatment with AIs does not affect cognitive functions in post-menopausal hormone receptor-positive breast cancer patients. Table 1: Relationship between the duration of treatment with AIs and MoCA and SMMT scoresDuration of AInMoCA*Mean±SDMoCAMed (min-max)SMMT**Mean±SDSMMTMed (min-max)0-6 m2319,7±5,221 (10-26)25±425 (15-30)6-12 m2420,7±5,421,5 (8-28)24,7±3,624 (16-30)12-24 m1418,2±4,118,5 (13-27)24,3±425 (13-29)24-36 m2920,3±4,920 (11-29)24,1±3,225 (17-30)36 m and more11020,3±4,521 (8-29)25±3,225 (14-30)Total20020.1±4,721 (8-29)24,8±3,425 (13-30)AI: Aromatase inhibitors, m: Mounths, n: Number, MoCA: Montreal Cognitive Assessment, SMMT: Standardized Mini-Mental State Examination, SD: Standart Deviation, Med: Median*p: 0.550 **p:0.533 Citation Format: Rukiye Guler Ilhan, Yusuf Ilhan, Sema Sezgin Goksu, Ali Murat Tatli, Hasan Senol Coskun. The effect of using adjuvant aromatase inhibitors on cognitive functions in postmenopausal women with hormone receptor-positive breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-71.

Frequency of high-risk hormone receptor-positive breast cancer patients was much higher in Japanese breast cancer patients with germline BRCA1/2 mutations than in sporadic breast cancer patients.

Frequency of high-risk hormone receptor-positive breast cancer patients was much higher in Japanese breast cancer patients with germline BRCA1/2 mutations than in sporadic breast cancer patients.

Gene Expression Signatures of BRCAness and Tumor Inflammation Define Subgroups of Early-Stage Hormone Receptor-Positive Breast Cancer Patients.

Patients with estrogen receptor- and/or progesterone receptor-positive, early breast cancer benefit from hormonal treatment, yet high global death burdens due to high prevalence and long-term recurrence risk call for biomarkers to guide additional treatment approaches. From a prospective, observational study of postmenopausal early breast cancer patients treated with tamoxifen or aromatase inhibitors, gene expression analyses of 612 tumors was performed using the NanoString Breast Cancer 360 panel to interrogate 23 breast cancer pathways. Candidate signatures associated with disease subtype and event-free survival (EFS) were obtained by cluster analysis, Cox modeling, and conditional inference trees, and were independently tested in 613 patients from BreastMark. Tumor-infiltrating lymphocytes (TIL) were assessed on tissue sections, and mutational burden was assessed in 36 tumors by whole-exome sequencing. PAM50-derived classification distinguished lower-risk (Luminal A) from higher-risk subtypes (Luminal B, P = 0.04; HER2, P = 0.006; Basal, P = 0.008). In higher-risk patients, shorter EFS was associated with low androgen receptor [HR = 3.61; 95% confidence interval (CI), 1.72-7.56; P = 0.001] or high BRCAness signature expression (HR = 3.58; 95% CI, 1.19-10.7; P = 0.023). BRCAness was independently confirmed as a predictor of shorter EFS (HR = 2.64; 95% CI, 1.31-5.34; P = 0.007). About 13%-15% of patients, enriched for high-grade, higher-risk subtypes (P ≤ 0.0001), had strong expression of the Tumor Inflammation Signature (TIS) suggestive of an inhibited antitumor immune response. TIS scores were strongly associated with TIL numbers (P < 1e-30) but not with tumor mutation status. BRCA-related DNA repair deficiency and suppressed tumor immune responses may be clinically relevant predictors of endocrine therapy complementing treatment options in subgroups of hormone-sensitive early breast cancer.

Cancer stem cells: Culprits in endocrine resistance and racial disparities in breast cancer outcomes.

Breast cancer stem cells (BCSCs) promote endocrine therapy (ET) resistance, also known as endocrine resistance in hormone receptor (HR) positive breast cancer. Endocrine resistance occurs via mechanisms that are not yet fully understood. In vitro, in vivo and clinical data suggest that signaling cascades such as Notch, hypoxia inducible factor (HIF), and integrin/Akt promote BCSC-mediated endocrine resistance. Once HR positive breast cancer patients relapse on ET, targeted therapy agents such as cyclin dependent kinase inhibitors are frequently implemented, though secondary resistance remains a threat. Here, we discuss Notch, HIF, and integrin/Akt pathway regulation of BCSC activity and potential strategies to target these pathways to counteract endocrine resistance. We also discuss a plausible link between elevated BCSC-regulatory gene levels and reduced survival observed among African American women with basal-like breast cancer which lacks HR expression. Should future studies reveal a similar link for patients with luminal breast cancer, then the use of agents that impede BCSC activity could prove highly effective in improving clinical outcomes among African American breast cancer patients.

Comprehensive Transcriptomic Analysis Reveals Dysregulated Competing Endogenous RNA Network in Endocrine Resistant Breast Cancer Cells.

BackgroundTamoxifen and fulvestrant, both approved for endocrine therapy, have remarkably increased the prognosis of hormone receptor-positive breast cancer patients. However, acquired resistance to endocrine therapy greatly reduces its clinical efficacy. Accumulating evidence suggests a pivotal role of non-coding RNAs (ncRNAs) in breast cancer endocrine resistance, but the specific functions of ncRNAs in tamoxifen and fulvestrant resistance remain largely unknown.MethodsMicroarray analysis was performed for endocrine therapy sensitive (MCF-7), tamoxifen-resistant (LCC2), and dual tamoxifen and fulvestrant-resistant (LCC9) breast cancer cells. Gene ontology and pathway analysis were conducted for functional prediction of the unannotated differentially expressed ncRNAs. Competing endogenous RNA regulatory networks were constructed.ResultsWe discovered a total of 3,129 long non-coding RNAs (lncRNAs), 13,556 circular RNAs (circRNAs), 132 microRNAs, and 3358 mRNAs that were significantly differentially expressed. We constructed co-expression networks for lncRNA-mRNA, circRNA-mRNA, and microRNA-mRNA. In addition, we established lncRNA-microRNA-mRNA and circRNA-microRNA-mRNA regulatory networks to depict ncRNA crosstalk and transcriptomic regulation of endocrine resistance.ConclusionsOur study delineates a comprehensive profiling of ncRNAs in tamoxifen and fulvestrant resistant breast cancer cells, which enriches our understanding of endocrine resistance and sheds new light on identifying novel endocrine resistance biomarkers and potential therapeutic targets to overcome endocrine resistance.

Palbociclib combined with endocrine therapy in heavily pretreated HR+/HER2- advanced breast cancer patients: Results from the compassionate use program in Spain (PALBOCOMP)

BackgroundThis study evaluated efficacy and safety of palbociclib, a CDK4/6 inhibitor, in heavily-pretreated hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) patients during the compassionate use program in Spain from February 2015 to November 2017. Patients and methodsPatient data were collected retrospectively from 35 hospitals in Spain. Patients with HR+/HER2- mBC who had progressed on ≥4 treatments for advanced disease were eligible. ResultsA total of 219 patients received palbociclib in combination with aromatase inhibitors (110; 50.2%), fulvestrant (87; 39.7%), tamoxifen (8; 3.6%) or as single agent (10; 4.6%). Mean age of the patients was 58 years; 31 patients (16.1%) were premenopausal and 162 (83.9%) were postmenopausal at the beginning of treatment with palbociclib. Patients had received a median of 3 previous lines of endocrine therapy (ET) for advanced disease. Real-world tumor response (rwTR) and clinical benefit rate were 5.9% (n = 13) and 46.2% (n = 101), respectively. The median real world progression-free survival (rwPFS) was 6.0 months (95% CI 5.7–7.0) and the median overall survival was 19.0 months (95% CI 16.4–21.7). Subgroup analysis revealed a significant difference in median rwPFS in patients treated with palbociclib plus fulvestrant depending on the duration of prior treatment with fulvestrant monotherapy (>6 versus ≤6 months; HR 1.93, 95% CI 1.37–2.73, p < 0.001). The most frequently reported toxicities were neutropenia, asthenia, thrombopenia and anemia. ConclusionsPalbociclib can be an effective and safe treatment option in patients with heavily pretreated endocrine-sensitive mBC, especially in those with longer PFS to previous ET.

Real-world experience of palbociclib and ribociclib: novel oral therapy in metastatic breast cancer.

Background Palbociclib and ribociclib are novel oral agents in hormone receptor-positive metastatic breast cancer. Neutropenia is a common adverse event associated with these treatments and its clinical management often requires regimen changes, such as cycle delays and dose adjustments. Objective To provide a real-world experience of the effectiveness and toxicities associated with these drugs and to evaluate the impact of regimen changes in disease progression. Setting This study was performed at Hospital Universitario La Paz, in Spain. Methods Observational, retrospective study which included hormone receptor-positive metastatic breast cancer patients who initiated treatment with palbociclib or ribociclib between March 1st, 2018 and March 1st, 2019. Main outcome measure The primary effectiveness variable was progression-free survival. Safety evaluation was performed to determine neutropenia-incidence and severity, as well as its clinical management, including dose adjustments and treatment interruptions. Correlations between these regimen changes and effectiveness were also evaluated. Results Sixty-one patients were included, 33 treated with palbociclib and 28 with ribociclib. Palbociclib was mainly used as second line of treatment in the metastatic setting (81.8%) and ribociclib as first line (67.9%). The median progression-free survival was 12.76months (95% CI 7.5 to not estimable) in palbociclib and not reached in ribociclib. After 12months, the progression-free survival rate was 51.5% (95% CI 34-69) in palbociclib and 78.6% (95% CI 63-94.1) in ribociclib. Neutropenia was the most common adverse event with an incidence rate of 87.9% in palbociclib and 82.1% in ribociclib. Cycle delays were needed in more than half of the patients treated with palbociclib and ribociclib (63.6% and 64.3%). Dose adjustments were seen in 42.4% and 53.6% of the patients receiving palbociclib and ribociclib, respectively. Regimen changes did not involve statistically significant differences in 12-month PFS rates in the cohort investigated. Conclusion Palbociclib and ribociclib outcomes are comparable to those reached in the phase III trials, PALOMA-3 and MONALEESA-2, respectively, and cannot be compared as they were used in different treatment settings. The toxicity profile is favourable, being neutropenia the most common adverse event, easily managed with regimen changes. Further studies are needed to confirm the observed tendency of no detrimental impact on effectiveness of these regimen changes.

Genetic ablation of pregnancy zone protein promotes breast cancer progression by activating TGF-β/SMAD signaling.

Pregnancy zone protein (PZP) is best known as protease inhibitor and its concentration in human blood plasma increases dramatically during pregnancy. Recent investigation revealed a role of PZP inactivating germ-line mutation in breast cancer predisposition, and therefore we designed a study to evaluate functional involvement of this protein in tumor pathogenesis. PZP knockout cells were generated utilizing the CRISPR-Cas9 approach in MCF7 and T47D (breast cancer) cell lines, and colony formation, cell proliferation, and migration assays carried out. TGF-β and SMAD expression studies were performed using qRT-PCR and Western blot. PZP expression in tumor vs normal tissue was compared using meta-analyses of data records of breast cancer patients (n = 1211) included in the TCGA consortium registry as well as in independent cohorts of hormone receptor-positive (n = 118) and triple-negative breast cancer (TNBC) patients (n = 116). We demonstrated that genetic ablation of PZP efficiently inhibits tamoxifen-induced apoptosis and enhances cell proliferation, migration, and colony-forming capacity. We found a significant increase in survival fraction of CRISPR/Cas9-mediated PZP knockout clones compared to wild-type counterpart after tamoxifen treatment (p < 0.05). The PZP knockout significantly promoted breast cancer cell migration (p < 0.01) in vitro. We observed high expression of TGF-β2 ligand, TGF-β- receptor 2, and upregulation of phosphorylated regulatory-SMADs (pSMAD2 and pSMAD3) activating the pro-survival function of TGF-β/SMAD signaling in PZP knockout clones. Meta-analyses of data records of breast cancer patients indicated that low PZP expression is associated with poor overall survival at 6years (51.7% vs 62.9% in low vs high expressers, respectively; p = 0.026). We alsoobserved a significantly lower PZP mRNA expression in TNBC as compared with hormone receptor-positive tumors (p = 0.019). Taken together, our results suggest that genetic ablation of PZP results in tumor progression and low expression of PZP is associated with poor survival of breast cancer patients.

153 Poster - Chitinase-like proteins as candidate markers for tamoxifen responsiveness

Background: The interplay between the tumor cells and regulatory microenvironment proteins such as chitinase-like proteins YKL-39, YKL-40, SI-CLP and stabilin-1 may play a critical role in the disease progression and response to treatment. The aim of this study was to examine the expression levels of the CHI3L2, CHI3L1, CHID1, STAB1 gene coding chitinase-like proteins in relation to tamoxifen treatment in hormone-receptor positive breast cancer patients; and the relationship between these levels and expression of Akt1-associated genes.

Treatment interruption and discontinuationof hormonal therapy in hormone receptor-positive breast cancer patients.

To investigate predictors of treatment interruption and early discontinuation of adjuvant hormonal therapy (HT) in a retrospective cohort of women with newly diagnosed hormone receptor-positive (HR +) breast cancer. Eligible cases were identified from a single institutional tumor registry from 2009 to 2015. Patients were followed from initiation of adjuvant HT for a minimum of one year through December 1, 2016. Predictors of treatment interruption or early discontinuation were analyzed with Cox proportional hazards regression models. With a median follow-up time of 3.0years (IQR 1.5-4.5), 22 women (10.9%) discontinued HT early and 47 (23.4%) had at least one treatment interruption of > 14days. Adjusted Cox proportional hazards regression models showed that women with pre-existing affective disorders were more likely to discontinue therapy early (HR 3.15; 95% CI 1.35-7.37), while those with pre-existing chronic pain disorders were at increased risk for treatment interruption (HR 2.24; 95% CI 1.20-4.19). HT-related symptoms were the most commonly reported reason for HT interruption or discontinuation. Women who experienced severe treatment-related symptoms were at increased risk for both HT interruption (HR 2.64; 95% CI 1.07-6.50) and HT discontinuation (HR 3.48; 95% CI 1.20-10.1). This study showed that HT interruptions and discontinuation were common, often associated with HT-related symptoms. Clinicians caring for breast cancer patients on HT should monitor closely for treatment-emergent symptoms, especially women with pre-existing disorders, and support them to continue therapy through aggressive symptom management and other patient-centered approaches.

Abstract 6323: Identification of genomic alterations related to treatment progression in RWD

Abstract Real-world data (RWD) are potentially a highly valuable resource to accelerate drug discovery and improve clinical practice. In particular, datasets combining clinical outcomes and comprehensive genomic profiling (CGP) could uncover new mechanisms of resistance and identify new patient populations for targeted therapies. Here, we used a de-identified clinico-genomic database (CGDB) from routine clinical care based on a clinical EHR-derived data from Flatiron Health linked to tumor sequencing results from Foundation Medicine to assess how prevalence of genomic alterations changes following progression on targeted therapies in the metastatic setting. One of the main challenges we faced is the lack of systematic and longitudinal genomic testing: among the patients receiving a specific treatment, some had a CGP performed prior to treatment, others only around the end of the line of therapy, but only a handful had multiple tests. We therefore established a methodology to assess changes in alteration prevalence and tested how our results are sensitive to cohort building parameters such as timing of testing, duration of therapy, or prior lines of treatment. Our approach successfully recovered three established cases of therapeutic resistance: (1) EGFR T790M in non-small cell lung cancer patients treated with erlotinib or gefitinib; (2) AR alterations following hormonal therapies in prostate cancers; and (3) ESR1 mutations in hormone-receptor positive breast cancer patients progressing on endocrine therapies other than fulvestrant. We delved into the latter case and identified differences in the type of ESR1 mutation that occurred following endocrine therapies if CDK4/6 inhibitors were co-administered or not. On one hand, RWD lack randomization and can thus be subject to confounding variables but on the other hand, RWD have the advantage of including a larger number of patients in a real-world setting compared to clinical trials. Our analysis shows that real-world CGDB can recapitulate the expected emergence of mutations following specific lines of treatment. Our study is a proof of concept of usage of RWD to assess how prevalence of genomic alterations changes following treatment. Our method allowed us to assess differences between patient cohorts and generate novel hypotheses on treatment-related changes in genomic profiles, which can ultimately lead to new drug indications. Citation Format: Nayan Chaudhary, Patricia Luhn, Gunther Jansen, Ciara Metcalfe, Marc Hafner. Identification of genomic alterations related to treatment progression in RWD [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6323.

Adjuvant endocrine therapy is associated with improved overall survival in elderly hormone receptor-positive breast cancer patients.

There is controversy regarding the survival benefit of endocrine therapy (ET) in elderly patients with early invasive hormone receptor-positive (HR+) breast cancer. In this study, we characterize a single institution's practice patterns using adjuvant ET for these patients and evaluated the effect of ET on outcomes. A review of a prospectively maintained database identified 483 women ≥ 70years old who underwent breast -conserving surgery (BCS) for stage I-III HR+ tumors from 2004-2013. We compared clinicopathologic characteristics, overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and breast cancer-specific survival (BCSS) in patients who did and did not receive ET. Compared to patients who did not get ET, patients who received ET were younger (median age 76 vs 78years, p = 0.006), had larger tumors (median size 15 vs 14mm, p = 0.016), underwent sentinel lymph node (LN) biopsy (83.7 vs 67.8%, p < 0.001), had positive LNs (25.5 vs 9.8%, p = 0.008), and received radiation (XRT, 76 vs 43%, p < 0.001). After adjusting for ASA score, age, LN status, tumor grade, and XRT, receipt of ET was associated with improved OS (HR 0.44; 95% CI 0.25-0.77; p = 0.004) and DFS (HR 0.42; 95% CI 0.28-0.64; p < 0.01). Receipt of ET was associated with improved LRR on univariate analysis (HR 0.25; 95% CI 0.09-0.70; p = 0.008); however, after adjusting for grade and XRT, this was not statistically significant on multivariable analysis (HR 0.38; 95% CI 0.13-1.08; p = 0.069) and was not associated with BCSS (HR 0.59; 95% CI 0.16-2.16; p = 0.43). ET was associated with significant improvements in OS and DFS, regardless of clinicopathological features; however, receipt of ET did not impact LRR and BCSS.

Post-neoadjuvant treatment of breast cancer

Achieving a pathologic complete response as a result of neoadjuvant treatment is associated with improved prognosis in breast cancer. The CREATE-X trial showed a significant survival improvement with capecitabine treatment of patients with residual invasive disease following neoadjuvant chemotherapy, and the KATHERINE trial demonstrated a significant benefit of trastuzumabemtansine (TDM1) in patients with HER2-positive breast cancer who did not achieve a pathologic complete response, so we have a lot of interesting alternatives of post-neoadjuvant treatments for high-risk patients. The discovery of molecular markers of resistance to endocrinotherapy (cyclin-dependent kinases (CDK 4/6), ER mutation (ESR1), mTOR signaling pathway, co-expression of ER+/HER2+) and inhibitors to them expanded the possibilities of endocrinotherapy not only in advanced and metastatic breast cancer, but also in residual ER+ tumors. The pCR rates in hormone receptor-positive breast cancer after neoadjuvant chemotherapy are around 10%, which is much lower than the values observed in HER2-positive and triple negative subtypes, so new strategies are needed to improve pCR rates in this subgroup, even though the adjuvant endocrine therapy impacts significantly the outcomes of this patients. The cyclin-dependent kinases (CDKs) are serine–threonine kinases that regulate cell cycle progression from the G1 to the S-phase during mitosis. CDKs activity can be abnormally increased or dysregulated in breast cancer, leading to a constant stimulus for cell proliferation and survival, which is a known mechanism of resistance to endocrine treatment. The CDK inhibitors act on CDKs and block their activity, thereby restoring the cell cycle regulation. In studies with metastatic hormone receptor-positive breast cancer patients, the combination of a CDKis with first or second-line endocrine therapy showed significant improvements in progression-free survival and response rates. Evolving techniques such as next-generation sequencing and gene expression profiles have improved our understanding of the biology of residual disease and also the mechanisms involved in treatment resistance.

Independent Prognostic Value of Intratumoral Heterogeneity and Immune Response Features by Automated Digital Immunohistochemistry Analysis in Early Hormone Receptor-Positive Breast Carcinoma.

Immunohistochemistry (IHC) for ER, PR, HER2, and Ki67 is used to predict outcome and therapy response in breast cancer patients. The current IHC assessment, visual or digital, is based mostly on global biomarker expression levels in the tissue sample. In our study, we explored the prognostic value of digital image analysis of conventional breast cancer IHC biomarkers supplemented with their intratumoral heterogeneity and tissue immune response indicators. Surgically excised tumor samples from 101 female patients with hormone receptor-positive breast cancer (HRBC) were stained for ER, PR, HER2, Ki67, SATB1, CD8, and scanned at 20x. Digital image analysis was performed using the HALO™ platform. Subsequently, hexagonal tiling was used to compute intratumoral heterogeneity indicators for ER, PR and Ki67 expression. Multiple Cox regression analysis revealed three independent predictors of the patient's overall survival: Haralick's texture entropy of PR (HR = 0.19, p = 0.0005), Ki67 Ashman's D bimodality (HR = 3.0, p = 0.01), and CD8+SATB1+ cell density in tumor tissue (HR = 0.32, p = 0.02). Remarkably, the PR and Ki67 intratumoral heterogeneity indicators were prognostically more informative than the rates of their expression. In particular, a distinct non-linear relationship between the rate of PR expression and its intratumoral heterogeneity was observed and revealed a non-linear prognostic effect of PR expression. The independent prognostic significance of CD8+SATB1+ cells infiltrating the tumor could indicate their role in anti-tumor immunity. In conclusion, we suggest that prognostic modeling, based entirely on the computational image-based IHC biomarkers, is possible in HRBC patients. The intratumoral heterogeneity and immune response indicators outperformed both conventional breast cancer IHC and clinicopathological variables while markedly increasing the power of the model.

Abstract 29: Utility of novel clinico-genomic data to understand patient characteristics, treatments, and outcomes according to PIK3CA mutation status among hormone receptor-positive metastatic breast cancer patients

Abstract Background: Hormone receptor-positive (HR+) breast cancer (BC) comprises 60-65% of all BC. Activating mutations in PIK3CA are the most common oncogenic alteration in HR+ BC, yet little is known about the prognostic utility of single (SM) and multiple (MM) PIK3CA mutations. A novel database with next-generation sequencing (NGS) data from Foundation Medicine, Inc. (FMI) linked to electronic health records-derived clinical data from Flatiron Health allows investigation of the prognostic utility of genomic alterations including PIK3CA. Using this database, this study seeks to understand HR+/human epidermal growth factor receptor 2-negative (HER2-) metastatic BC (mBC) patient (pt) testing behavior, characteristics, and survival according to PIK3CA mutation status. Methods: Pt-level data from US pts diagnosed with HR+/HER2- mBC from January 1, 2011 to December 31, 2018 were selected from the de-identified Flatiron Health-FMI Clinico-Genomic Database (CGDB). Kaplan-Meier methods were used to estimate median (95% confidence interval [CI]) survival time, defined as time from mBC diagnosis to death. Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% CIs. Index date was mBC diagnosis date, but adjustments were made in survival analyses to account for delayed dataset entry due to FMI results date occurring after mBC diagnosis date. Descriptive statistics and chi-square and Kruskal-Wallis tests for significance were used to compare pt characteristics. Results: Of 1349 HR+/HER2- mBC pts included in this study, 807 pts (60%) were wild-type (WT) for PIK3CA, 436 (32%) were SM, and 106 (8%) were MM. Only 2% of pts had an FMI results date before mBC diagnosis date. Most pts had an FMI results date either during (26%) or after (59%) first-line treatment. Median time from mBC diagnosis to FMI results date was longer for MM (19 mo) vs. SM (13 mo) and WT (13 mo) pts (p=0.15). SM and MM pts were older than WT pts at mBC diagnosis (median: 59.9 yr [MM] vs. 59.6 yr [SM] vs. 56.2 yr [WT], p&amp;lt;0.001) and more often had progesterone receptor (PR)-positive BC (88.6% [MM] vs. 86.5% [SM] vs. 74.6% [WT], p&amp;lt;0.001). Median survival times for WT, SM, and MM pts were 20, 23, and 30 mo, respectively (p=0.40). After adjusting for age, site of metastasis at mBC diagnosis, and estrogen receptor/PR status, there was no association with overall survival for MM vs. WT (HR=0.96, p=0.53) or SM vs. WT (HR=1.03, p=0.80). Conclusions: These data showed that PIK3CA mutations were not associated with survival in this patient population and underscore the utility of linked clinical and genomics data for understanding the relationship between genetic alterations and patient outcomes. The majority of HR+/HER2- mBC pts received FMI results more than a year after mBC diagnosis, suggesting that NGS testing is used to guide decisions after pts have failed standard therapy. Additional studies with larger sample sizes and longer follow-up are needed to confirm these observations. Citation Format: Mary K. Downer, Peter Lambert, Sami Mahrus, Katherine E. Hutchinson, Patricia Luhn, Jennifer L. Schutzman. Utility of novel clinico-genomic data to understand patient characteristics, treatments, and outcomes according to PIK3CA mutation status among hormone receptor-positive metastatic breast cancer patients [abstract]. In: Proceedings of the AACR Special Conference on Advancing Precision Medicine Drug Development: Incorporation of Real-World Data and Other Novel Strategies; Jan 9-12, 2020; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_1):Abstract nr 29.