Citations

We assessed the effect of right ventricular afterload reduction with sildenafil and heart rate reduction with metoprolol on cardiac hemodynamics and function in young adults born premature using 4D flow MRI. Metoprolol depressed cardiac function, whereas sildenafil improved cardiac function including right ventricular direct flow fraction by 4D flow, consistent with hemodynamic improvement. This suggests that the preterm heart is dependent on heart rate and sensitive to right ventricular afterload changes.Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/behind-the-bench-episode-9 .

Abstract Purpose: To determine genetic variants that could differentiate aromatase inhibitors (AIs) efficacy in early stage breast cancer. Experimental Design: We performed a stratified cox-proportional hazards analysis utilizing stratification factors and other covariates examining Breast Cancer Free Interval (BCFI) SNP-treatment interaction in Caucasian patients entered on the MA.27 trial. This analysis involved 4465 patients (2226 on anastrozole and 2239 on exemestane arm) including 245 (121 on anastrozole and 124 events on exemestane arm) with a breast event. Preclinical laboratory studies included luciferase activity, chromatin immunoprecipitation (ChIP) assay, and cell migration assays. Results: We identified 887 SNPs with a p-value <1E-4 that could differentiate anastrozole from exemestane efficacy. We next used GTEx databases to determine whether these SNPs might be cis-eQTLs with nearby genes, and found that 95 SNPs were eQTL with 14 genes. Functional validation of SNP effect in these 14 genes on response to anastrozole and exemestane revealed that 3 SNPs showed genotype-dependent differences between anastrozole and exemestane. Two of the three SNPs, rs1877193 and rs6735923 located upstream of LY75 gene, were associated with higher LY75 gene expression. Our drug-SNP interaction GWAS showed that both SNPs were associated with better BCFI for exemestane compared to anastrozole (HR= 0.447, 0.458). The SNP rs62293499 located downstream of the GPR160 gene was also associated with better BCFI for exemestane compared to anastrozole (HR=0.433). Interestingly, all 3 SNPs were associated with worse outcome (shorter BCFI) in anastrozole treated patients (HR=1.39~1.58), but with longer BCFI in the exemestane treated patients (HR=0.58~0.71) based on our GWAS results in MA.27 trial. However, all 3 SNPs showed no association with BCFI if the two treatment arms, anastrozole and exemestane, were combined (HR=0.92~1.08). Consistently, cells with Ly75 or GPR160 SNP variant genotypes were more sensitive to exemestane compared to anastrozole. Mechanistically, the 3 SNPs regulated estrogen receptor-dependant LY75 and GPR160 expression. LY75 suppression induced epithelial-to-mesenchymal transition (EMT) in breast cancer cell lines, accompanied by increased migratory capacity in vitro. LY75 knockdown also resulted in predominant downregulation of functional pathways such as cell proliferation, while pathways associated with mesenchymal stimulation were generally increased. GPR160 knockdown also resulted in downregulation of cell proliferation pathways. Conclusions: This SNP genotype and AI treatment interaction clinical study revealed unique genetic variants that differentiate anastrozole and exemestane efficacy. The signals were lost in the GWAS analysis when anastrozole and exemestane were combined. Preclinical laboratory studies revealed novel functions of LY75 and GPR160 in breast cancer. These findings represent potential steps towards individualized AI therapy. Citation Format: Junmei Cairns, James N. Ingle, Krishna R. Kalari, Lois E. Shepherd, Matthew J. Ellis, Paul E. Goss, Poulami Barman, Erin E. Carlson, Matthew P. Goetz, Richard M. Weinshilboum, Liewei Wang. The interaction between SNP genotype and aromatase inhibitor treatment response in early breast cancer [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 LB-103.

Aromatase inhibitors (AIs) reduce breast cancer recurrence and prolong survival, but up to 30% of patients exhibit recurrence. Using a genome-wide association study of patients entered on MA.27, a phase III randomized trial of anastrozole versus exemestane, we identified a single nucleotide polymorphism (SNP) in CUB And Sushi multiple domains 1 ( CSMD1) associated with breast cancer–free interval, with the variant allele associated with fewer distant recurrences. Mechanistically, CSMD1 regulates CYP19 expression in an SNP- and drug-dependent fashion, and this regulation is different among 3 AIs: anastrozole, exemestane, and letrozole. Overexpression of CSMD1 sensitized AI-resistant cells to anastrozole but not to the other 2 AIs. The SNP in CSMD1 that was associated with increased CSMD1 and CYP19 expression levels increased anastrozole sensitivity, but not letrozole or exemestane sensitivity. Anastrozole degrades estrogen receptor α (ERα), especially in the presence of estradiol (E2). ER + breast cancer organoids and AI- or fulvestrant-resistant breast cancer cells were more sensitive to anastrozole plus E2 than to AI alone. Our findings suggest that the CSMD1 SNP might help to predict AI response, and anastrozole plus E2 serves as a potential new therapeutic strategy for patients with AI- or fulvestrant-resistant breast cancers.

Objectives Based on our previous findings that postmenopausal women with estrone (E1) and estradiol (E2) concentrations at or above 1.3 pg/ml and 0.5 pg/ml, respectively, after 6 months of adjuvant anastrozole therapy had a three-fold risk of recurrence, we aimed to identify a single-nucleotide polymorphism (SNP)-based model that would predict elevated E1 and E2 and then validate it in an independent dataset. Patients and methods The test set consisted of 322 women from the M3 study and the validation set consisted of 152 patients from MA.27. All patients were treated with adjuvant anastrozole, had on-anastrozole E1 and E2 concentrations and genome-wide genotyping. Results SNPs were identified from the M3 genome-wide association study. The best model to predict the E1-E2 phenotype with high balanced accuracy was a support vector machine model using clinical factors plus 46 SNPs. We did not have an independent cohort that is similar to the M3 study with clinical, E1-E2 phenotypes and genotype data to test our model. Hence, we chose a nested matched case-control cohort (MA.27 study) for testing. Our E1-E2 model was not validated but we found the MA.27 validation cohort was both clinically and genomically different. Conclusions We identified a SNP-based model that had excellent performance characteristics for predicting the phenotype of elevated E1 and E2 in women treated with anastrozole. This model was not validated in an independent dataset but that dataset was clinically and genomically substantially different. The model will need validation in a prospective study.

Abstract Objective: The aim of the study was to quantify baseline estradiol (E2) and estrone (E1) concentrations according to selected patient characteristics in a substudy nested within the MAP.3 chemoprevention trial. Methods: E2 and E1 levels were measured in 4,068 postmenopausal women using liquid chromatography-tandem mass spectrometry. Distributions were described by age, years since menopause, race, body mass index (BMI), smoking status, and use and duration of hormone therapy using the Kruskal-Wallis test. Multivariable linear regression was also used to identify characteristics associated with estrogen levels. Results: After truncation at the 97.5th percentile, the mean (SD)/median (IQR) values for E2 and E1 were 5.41 (4.67)/4.0 (2.4-6.7) pg/mL and 24.7 (14.1)/21 (15-31) pg/mL, respectively. E2 and E1 were strongly correlated (Pearson correlation [ r ] = 0.8, P < 0.01). The largest variation in E2 and E1 levels was by BMI; mean E2 and E1 levels were 3.5 and 19.1 pg/mL, respectively for women with BMI less than 25 and 7.5 and 30.6 pg/mL, respectively, for women with BMI greater than 30. E2 and E1 varied by age, BMI, smoking status, and prior hormone therapy in multivariable models ( P < 0.01). Conclusions: There was large interindividual variability observed for E2 and E1 that varied significantly by participant characteristics, but with small absolute differences except in the case of BMI. Although the majority of participant characteristics were independently associated with E1 and E2, together, these factors only explained about 20% of the variation in E1 and E2 levels.

564 Background: Our group previously examined if baseline patient/tumor characteristics, or prior treatment affected cause of death in MA.17, a placebo controlled extended adjuvant trial of the aromatase inhibitor (AI) letrozole. We now examine factor effects on all cause mortality in MA.27. Methods: MA.27 was an adjuvant phase III superiority trial of 5 yrs of exemestane vs anastrozole, in ER+ postmenopausal breast cancer accrued between 2003 and 2008; event free survival was similar. We examined by intention-to-treat, the multivariate time-to-breast cancer-specific (BrCa), cardiovascular (Cardio), and other causes (OT) of death with log-normal survival analysis adjusted by treatment and stratification factors (lymph node status, adjuvant chemotherapy, celecoxib, aspirin, and trastuzumab). We tested whether factors were associated with 1) all cause mortality, and if so, 2) cause-specific mortality. We also fit step-wise forward cause-specific adjusted models. Results: 7,576 women (median age 64.1 years; 5417 (71.5%) <70 yrs and 2159 (28.5%) >70 yrs) were enrolled and followed for a median of 4.1 yrs. The 432 deaths comprised: 187 (43.3%) BrCa, 66 (15.3%) Cardiovascular, and 179 (41.4%) OT MA.27 therapy was not associated with mortality (p=0.84). Five baseline factors were differentially associated with cause of death. Older age was associated with greater BrCa (p=0.03), Cardio (p<0.001), and OT (p<0.001) mortality. Pre-existing cardiovascular history led to worse Cardio mortality (p<0.001). Worse ECOG performance status led to worse OT death (p<0.001). T1 tumors were associated with less BrCa mortality (p<0.001). PgR+ tumors were also associated with less BrCa mortality (p<0.001). There were fewer BrCa deaths with Node –ve disease (p<0.001), ER+ tumors (p=0.001) and without adjuvant chemotherapy (p=0.005); there was worse Cardio mortality (p=0.01) with receipt of trastuzumab; worse OT (p=0.03) for non-whites, and without adjuvant radiotherapy (p=0.003). Conclusions: 56.7% of deaths in MA.27 patients were non-breast cancer related. We showed baseline patient and tumor characteristics, and prior treatment differentially affected cause of death. Clinical trial information: NCT00066573.

6018 Background: Disease free survival was significantly improved in women receiving letrozole after standard adjuvant tamoxifen in the MA.17 trial. Based on the results of MA.17 and of other trials of aromatase inhibitors in early stage breast cancer, chronic aromatase inhibitor therapy, in postmenopausal women free of breast cancer recurrence, is now being widely employed. We analyzed the toxicity of letrozole according to ethnic status among women enrolled in MA.17. Methods: The chi-square test was used for comparison of rates of side effects between the two groups, Caucasian vs. ethnic minority (defined as all non-Caucasians). In a subset of women, quality of life (QOL) was assessed by the SF-36 Health Survey. Mean change scores in QOL from baseline were compared between groups for summary measures and domains using the Wilcoxon test. Results: 352 minority women and 4,708 Caucasians were enrolled in MA.17, of which 183 minority women and 2,339 Caucasians were randomized to receive letrozole. Caucasians were older than minority women and had a slightly longer duration of treatment with prior tamoxifen. Tumor size and nodal status were not significantly different between the two groups. In women who received letrozole, minority women had significantly lower incidence of hot flashes (49% vs. 58%; p = 0.02), fatigue (29% vs. 39%; p = 0.005), and arthritis (2% vs. 7%; p = 0.006) compared with Caucasians. Mean QOL change scores of SF-36 domains for women who received letrozole were not different but minority women had better mental health at 6 month assessment (p = 0.02) and worse bodily pain at 12 month assessment (p = 0.046). Conclusions: Minority women tolerated letrozole considerably better than Caucasians in the MA.17 trial. These preliminary findings suggest that minority women respond differently to letrozole in terms of toxicity. Recent demonstration of genotypic variations in the aromatase gene in different ethnic groups plus likely pharmacogenomic differences suggests that further research is needed to clarify the clinical outcomes of aromatase inhibition in women of diverse ethnicities. Future research strategies should focus on examining in vivo genotype-phenotype correlations to determine the effects of genetic variation on response to anticancer therapy and on toxicities and end-organ effects. [Table: see text]

550 Background: 5187 postmenopausal women were originally randomized to NCIC CTG MA.17 to receive letrozole (LET) or placebo (PLAC) after 5 years of tamoxifen. The hazard ratio (HR) for disease-free survival (DFS) was 0.58 (0.450.76, p=0.00004) after a median follow-up of 30 months (mo). The trial was unblinded in October 2003 after the first interim analysis. Women randomized to PLAC were offered LET at the time of unblinding. The goal of this analysis was to determine whether women switching from PLAC to LET benefit in terms of disease outcome and to evaluate treatment related toxicities. Methods: LET and PLAC-LET have been compared to PLAC, based on the hazard ratio and adjusting for baseline patient and disease variables including, among others, tumor size, nodal status and prior adjuvant chemotherapy. Results: Information about their follow-up treatment after unblinding was available on 2268 women originally assigned to PLAC and who were free of recurrence and alive at the time of unblinding. Among them, 1655 crossed over from PLAC to LET while 613 elected no treatment. With 54 mo f/up the HR for DFS was 0.31 (0.18, 0.55: p<0.0001) favoring patients who crossed over to LET compared to those who stayed on no treatment. The treatment switch was well tolerated with no significant difference in bone fractures or cardiovascular events. An updated analysis of DFS, DDFS and OS by nodal and tumor receptor status, prior chemotherapy, menopausal status at the start of tamoxifen, and duration of prior tamoxifen therapy will be presented at the meeting. Conclusion: Women with hormone dependent breast cancer prescribed LET after a prolonged delay from completing tamoxifen experienced a significant improvement in outcome (DFS, DDFS, OS) and should be considered for this therapy. [Table: see text]

549 Background: MA.17 evaluated letrozole (LET) or placebo (PLAC) after 5 years of tamoxifen (Tam) and showed [median follow-up 30 months (mos)] significant improvement in disease-free survival (DFS) for LET [hazard ratio (HR) 0.57, p = 0.00008]. The trial was unblinded and PLAC patients (pts) were offered LET. An ITT analysis of all outcomes, before and after unblinding, based on the original randomization was performed. Methods: A stratified log-rank test was used to compare DFS, distant (D)DFS, overall survival (OS) and incidence of contra-lateral breast cancer (CBC). The Cox regression model used baseline stratification variables and two prespecified factors, menopausal status at the start of Tam and time on Tam. Subgroup analyses for DFS and OS were performed for the two prespecified subsets. All p-values were two-sided Results: 5187 pts were randomized at baseline and, at unblinding, 1655 of 2268 PLAC pts accepted LET. At median follow-up of 54 mos (range,16–86) 363 recurrences or CBC’s (144 LET and 219 PLAC) occurred; 118 LET and 176 PLAC pts had recurrent disease and 26 LET and 43 PLAC pts had CBC. 4 year DFS was 94.3% (LET) and 91.4% (PLAC) (HR 0.64; 95% CI, 0.52 - 0.79; p = 0.00002). Corresponding 4 year DDFS was 96.2% and 94.9% (HR 0.76; 0.58–0.99; p = 0.041). 4 year OS was 95.0% (LET) and 95.1% (PLAC) (HR 1.00; 0.78–1.28; p = 0.99). LET was equally effective in node +ve and -ve pts (i.e., similar HRs) in DFS. OS was not significantly different for LET and PLAC in any subgroup. The annual rate of CBC was 0.29% LET (0.18–0.40) and 0.47% PLAC (0.34–0.61); HR 0.61 (0.38–0.98) p = 0.037. 255 pts had died as of the data cut-off (128 LET and 127 PLAC). Conclusions: In this ITT analysis, pts originally randomized to LET within 3 months of stopping Tam did better than PLAC pts in DFS, DDFS and CBC, despite 73% of PLAC pts crossing to LET after unblinding. This highlights the strong beneficial effect of extended adjuvant therapy with LET. [Table: see text]

540 Background: Risk of death from other malignancies (OM) and other causes (OC) than breast cancer (BC) increases with age. Effects of baseline factors on type of death were assessed with competing risks analyses. Methods: In NCIC CTG MA.17, 5,187 women free of recurrent breast cancer after 5 years of tamoxifen were randomized to letrozole (L, 2,593 women) or placebo (P, 2,594 women). The primary endpoint was disease free survival (DFS), and secondary, overall survival (OS). Follow-up was to October 9, 2005: median 3.9 years, range <0.1 to 7.0 years. Effects of competing risks were examined for endpoints of BC, OM, and OC for 11 baseline trial factors: treatment, age, menopausal status, duration of prior tamoxifen, adjuvant radiotherapy, bone fracture, osteoporosis, cardiovascular disease, hormone receptor status, nodal status, adjuvant chemotherapy. Lagakos’ hierarchical method (Lagakos, Appl. Statist. 1978; 27:235–241) was used to test for differential effects of baseline factors on type of death (BC, OM, OC). Results: Rate of censoring was 97.8%, with 256 deaths (BC, 102; OM, 50; OC, 100; unknown, 4). Non-breast cancer deaths accounted for 60% of known deaths; 72%, for those ≥70 years; and 48%, for those <70 years. Two baseline factors differentially affected type of death. Women with cardiovascular disease were more likely to die from OC (p=0.02), while those with osteoporosis were more likely to die of OM (p=0.03). Age and nodal status had directionally similar effects. Older women had shorter survival from all 3 causes of death (p=0.01). Lymph node positivity was associated with worse survival (p=0.003). Conclusions: Extended L provides similar proportional benefit in improving DFS for all ages of women (Muss ref abstract SABCS 2006). However, the magnitude of competing non-breast cancer, and non-treatment related, causes of death needs to be considered more frequently, since with early detection and improved therapies, breast cancer patients may increasingly be expected to survive their disease to die from another cause. The novel association between baseline osteoporosis and other malignancies is being explored quantitatively. No significant financial relationships to disclose.