Mark Bouzyk

CYP2D6 Genotype and Tamoxifen Response in Postmenopausal Women with Endocrine-Responsive Breast Cancer: The Breast International Group 1-98 Trial

BACKGROUND Adjuvant tamoxifen therapy is effective for postmenopausal women with endocrine-responsive breast cancer. Cytochrome P450 2D6 (CYP2D6) enzyme metabolizes tamoxifen to clinically active metabolites, and CYP2D6 polymorphisms may adversely affect tamoxifen efficacy. In this study, we investigated the clinical relevance of CYP2D6 polymorphisms. METHODS We obtained tumor tissues and isolated DNA from 4861 of 8010 postmenopausal women with hormone receptor-positive breast cancer who enrolled in the randomized, phase III double-blind Breast International Group (BIG) 1-98 trial between March 1998 and May 2003 and received tamoxifen and/or letrozole treatment. Extracted DNA was used for genotyping nine CYP2D6 single-nucleotide polymorphisms using polymerase chain reaction-based methods. Genotype combinations were used to categorize CYP2D6 metabolism phenotypes as poor, intermediate, and extensive metabolizers (PM, IM, and EM, respectively; n = 4393 patients). Associations of CYP2D6 metabolism phenotypes with breast cancer-free interval (referred to as recurrence) and treatment-induced hot flushes according to randomized endocrine treatment and previous chemotherapy were assessed. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. RESULTS No association between CYP2D6 metabolism phenotypes and breast cancer-free interval was observed among patients who received tamoxifen monotherapy without previous chemotherapy (P = .35). PM or IM phenotype had a non-statistically significantly reduced risk of breast cancer recurrence compared with EM phenotype (PM or IM vs EM, HR of recurrence = 0.86, 95% CI = 0.60 to 1.24). CYP2D6 metabolism phenotype was associated with tamoxifen-induced hot flushes (P = .020). Both PM and IM phenotypes had an increased risk of tamoxifen-induced hot flushes compared with EM phenotype (PM vs EM, HR of hot flushes = 1.24, 95% CI = 0.96 to 1.59; IM vs EM, HR of hot flushes = 1.23, 95% CI = 1.05 to 1.43). CONCLUSIONS CYP2D6 phenotypes of reduced enzyme activity were not associated with worse disease control but were associated with increased hot flushes, contrary to the hypothesis. The results of this study do not support using the presence or absence of hot flushes or the pharmacogenetic testing of CYP2D6 to determine whether to treat postmenopausal breast cancer patients with tamoxifen.

Wnt signaling in triple negative breast cancer is associated with metastasis

BackgroundTriple Negative subset of (TN) Breast Cancers (BC), a close associate of the basal-like subtype (with limited discordance) is an aggressive form of the disease which convey unpredictable, and poor prognosis due to limited treatment options and lack of proven effective targeted therapies.MethodsWe conducted an expression study of 240 formalin-fixed, paraffin-embedded (FFPE) primary biopsies from two cohorts, including 130 TN tumors, to identify molecular mechanisms of TN disease.ResultsThe annotation of differentially expressed genes in TN tumors contained an overrepresentation of canonical Wnt signaling components in our cohort and others. These observations were supported by upregulation of experimentally induced oncogenic Wnt/β-catenin genes in TN tumors, recapitulated using targets induced by Wnt3A. A functional blockade of Wnt/β-catenin pathway by either a pharmacological Wnt-antagonist, WntC59, sulidac sulfide, or β-catenin (functional read out of Wnt/β-catenin pathway) SiRNA mediated genetic manipulation demonstrated that a functional perturbation of the pathway is causal to the metastasis- associated phenotypes including fibronectin-directed migration, F-actin organization, and invasion in TNBC cells. A classifier, trained on microarray data from β-catenin transfected mammary cells, identified a disproportionate number of TNBC breast tumors as compared to other breast cancer subtypes in a meta-analysis of 11 studies and 1,878 breast cancer patients, including the two cohorts published here. Patients identified by the Wnt/β-catenin classifier had a greater risk of lung and brain, but not bone metastases.ConclusionThese data implicate transcriptional Wnt signaling as a hallmark of TNBC disease associated with specific metastatic pathways.

Optimization of RNA extraction from FFPE tissues for expression profiling in the DASL assay

Formalin-fixed paraffin-embedded (FFPE) breast tumor tissues are readily available and represent a largely untapped, vast resource for molecular profiling of clinical samples with long-term follow-up data. We have optimized the conditions and parameters that result in the preparation of total RNA that is of the necessary quality for use in the DASL (cDNA-mediated annealing, selection, extension, and ligation) assay in which expression of 502 genes are analyzed simultaneously using as little as 100 ng of input RNA.

Prostate cancer genes associated with TMPRSS2–ERG gene fusion and prognostic of biochemical recurrence in multiple cohorts

Background:Recent studies have indicated that prostate cancer patients with the TMPRSS2–ERG gene fusion have a higher risk of recurrence. To identify markers associated with TMPRSS2–ERG fusion and prognostic of biochemical recurrence, we analysed a cohort of 139 men with prostate cancer for 502 molecular markers.Methods:RNA from radical prostatectomy tumour specimens was analysed using cDNA-mediated, annealing, selection, extension and ligation (DASL) to determine mRNAs associated with TMPRSS2–ERG T1/E4 fusion and prognostic of biochemical recurrence. Differentially expressed mRNAs in T1/E4-positive tumours were determined using significance analysis of microarrays (false discovery rate (FDR) <5%). Univariate and multivariate Cox regression determined genes, gene signatures and clinical factors prognostic of recurrence (P-value <0.05, log–rank test). Analysis of two prostate microarray studies (GSE1065 and GSE8402) validated the findings.Results:In the 139 patients from this study and from a 455-patient Swedish cohort, 15 genes in common were differentially regulated in T1/E4 fusion-positive tumours (FDR <0.05). The most significant mRNAs in both cohorts coded ERG. Nine genes were found prognostic of recurrence in this study and in a 596-patient Minnesota cohort. A molecular recurrence score was significant in prognosticating recurrence (P-value 0.000167) and remained significant in multivariate analysis of a mixed clinical model considering Gleason score and TMPRSS2–ERG fusion status.Conclusions:TMPRSS2–ERG T1/E4 fusion-positive tumours had differentially regulated mRNAs observed in multiple studies, the most significant one coded for ERG. Several mRNAs were consistently associated with biochemical recurrence and have potential clinical utility but will require further validation for successful translation.

Protein-Coding and MicroRNA Biomarkers of Recurrence of Prostate Cancer Following Radical Prostatectomy

An important challenge in prostate cancer research is to develop effective predictors of tumor recurrence following surgery to determine whether immediate adjuvant therapy is warranted. To identify biomarkers predictive of biochemical recurrence, we isolated the RNA from 70 formalin-fixed, paraffin-embedded radical prostatectomy specimens with known long-term outcomes to perform DASL expression profiling with a custom panel that we designed of 522 prostate cancer-relevant genes. We identified a panel of 10 protein-coding genes and two miRNA genes (RAD23B, FBP1, TNFRSF1A, CCNG2, NOTCH3, ETV1, BID, SIM2, LETMD1, ANXA1, miR-519d, and miR-647) that could be used to separate patients with and without biochemical recurrence (P < 0.001), as well as for the subset of 42 Gleason score 7 patients (P < 0.001). We performed an independent validation analysis on 40 samples and found that the biomarker panel was also significant at prediction of biochemical recurrence for all cases (P = 0.013) and for a subset of 19 Gleason score 7 cases (P = 0.010), both of which were adjusted for relevant clinical information including T-stage, prostate-specific antigen, and Gleason score. Importantly, these biomarkers could significantly predict clinical recurrence for Gleason score 7 patients. These biomarkers may increase the accuracy of prognostication following radical prostatectomy using formalin-fixed specimens.

Abstract S1-8: Outcome According to CYP2D6 Genotype among Postmenopausal Women with Endocrine-Responsive Early Invasive Breast Cancer Randomized in the BIG 1-98 Trial

Background: Available endocrine therapies, tamoxifen or aromatase inhibitors (AIs), are effective on average for the large population of postmenopausal women with steroid hormone-receptor positive early breast cancer, but many patients still relapse and die of their disease. Treatment selection may be improved by determining patient and disease features that suggest one or another endocrine therapy regimen is better for the individual patient. Recent clinical studies have presented conflicting evidence about whether postmenopausal women receiving adjuvant tamoxifen who carry genetic variants associated with low or absent CYP2D6 activity have a worse disease outcome. BIG 1-98 is a double-blind randomized trial comparing five years of the AI letrozole (Letx5), tamoxifen (Tamx5) and sequences of Let and Tam as adjuvant endocrine therapy for postmenopausal women with endocrine-responsive breast cancer. BIG 1-98 enrolled 8010 patients between 1998 and 2003. Results at 6 years median follow-up showed that, on average, Let was superior to Tam for disease-free and overall survival, and for time to distant recurrence. The sequential arms (Tamx2 → Letx3; Letx2 → Tamx3 had similar results compared with Let. Genotyping is underway using DNA extracted from tumor blocks of patients in trial BIG 1-98 to elucidate genetic determinants of interindividual variability in efficacy and side effects of adjuvant endocrine therapies. We hypothesize that variants of CYP2D6 are associated with shorter breast cancer-free interval on tamoxifen monotherapy, and that the relation will not be observed with letrozole monotherapy as a control. The association with sequential therapies is unknown and will be explored. Methods: Formalin-fixed, paraffin-embedded primary tumor specimens were reviewed in the IBCSG Central Pathology Laboratory and DNA isolated from one or two 1mm cores. Single nucleotide polymorphisms (SNPs) of CYP2D6 {including CYP2D6*4, *2, *3A, *6, *7, *10, *17, *41} were genotyped on the Beckman SNPstream or the ABI 7900 TaqMan system. The association of CYP2D6 variants with breast cancer-free interval and onset of hot flashes/night sweats will be investigated. The role of adjuvant chemotherapy, which was administered in about one-third of trial patients prior to randomization to adjuvant endocrine therapy, will also be investigated. Results: At this time, CYP2D6*4 has been genotyped from FFPE material of 2000 patients, with a success rate greater than 75%. The frequency of homozygous and heterozygous CYP2D6*4 was 8% and 18%, respectively, which is in line with anticipated allele frequency in a predominantly Caucasian population. Genotyping of additional CYP2D6 alleles is ongoing for these patients, as well as full genotyping for up to another 2000 patients. Conclusions: Trial BIG 1-98 provides a large, homogeneously-treated and followed cohort of patients treated with tamoxifen and other endocrine therapy regimens with available material for genotyping. Results of CYP2D6 genotyping (8 alleles) for all available patients will be presented at the meeting. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S1-8.

No Association between Polymorphisms in LEP, LEPR, ADIPOQ, ADIPOR1, or ADIPOR2 and Postmenopausal Breast Cancer Risk

There is evidence that adipokines such as leptin and adiponectin may influence breast tumor development. We conducted a nested case-control study using women in the American Cancer Society Cancer Prevention Study II to examine the association between postmenopausal breast cancer and variability in the genes encoding leptin, the leptin receptor, adiponectin, adiponectin receptor 1, and adiponectin receptor 2. Using 648 cases and 659 controls, we found no statistically significant (P < 0.05) associations between breast cancer risk and any of the single nucleotide polymorphisms. Individual odds ratios ranged from 0.93 to 1.06. We found no evidence of effect modification by body mass index, adult weight gain, location of weight gain, or physical activity. Although we cannot rule out that these genes are involved in gene-gene or gene-environment interactions, our results suggest that individual single nucleotide polymorphisms in these genes do not substantially affect postmenopausal breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2009;18(9):2553–7)

Serotonin transporter gene, depressive symptoms,and interleukin-6

Background— We explored the relationship of genetic variants of the serotonin transporter gene SLC6A4, a key regulator of the serotonergic neurotransmission, with both depressive symptoms and plasma interleukin-6 (IL-6) levels. Methods and Results— We genotyped 20 polymorphisms in 360 male twins (mean age, 54 years) from the Vietnam Era Twin Registry. Current depressive symptoms were measured with the Beck Depression Inventory II. IL-6 was assessed using a commercially available ELISA kit. Genotype associations were analyzed using generalized estimating equations. To study how SLC6A4 genetic vulnerability influences the relationship between depressive symptoms and IL-6, bivariate models were constructed using structural equation modeling. Of the 20 polymorphisms examined, the effective number of independent tests was 6, and the threshold of significance after Bonferroni correction was 0.008. There were 6 single-nucleotide polymorphisms significantly associated with Beck Depression Inventory (P≤0.008), including rs8071667, rs2020936, rs25528, rs6354, rs11080122, and rs8076005, and 1 single-nucleotide polymorphism was borderline associated (rs12150214, P=0.017). Of these 7 single-nucleotide polymorphisms, 3 were also significantly associated with IL-6 (P<0.008), including rs25528, rs6354, and rs8076005, and the other 4 were borderline associated (P=0.009 to 0.025). The subjects with 1 copy of the minor allele of these 7 single-nucleotide polymorphisms had higher Beck Depression Inventory scores and IL-6 levels. Further bivariate modeling revealed that ≈10% of the correlation between Beck Depression Inventory and IL-6 could be explained by the SLC6A4 gene. Conclusions— Genetic vulnerability involving the SLC6A4 gene is significantly associated with both increased depressive symptoms and elevated IL-6 plasma levels. Common pathophysiological processes may link depression and inflammation, and implicate the serotonin pathway in neural-immune interactions.

Differential activation of Wnt-β-catenin pathway in triple negative breast cancer increases MMP7 in a PTEN dependent manner.

Mutations of genes in tumor cells of Triple Negative subset of Breast Cancer (TNBC) deregulate pathways of signal transduction. The loss of tumor suppressor gene PTEN is the most common first event associated with basal-like subtype (Martins, De, Almendro, Gonen, and Park, 2012). Here we report for the first time that the functional upregulation of secreted-MMP7, a transcriptional target of Wnt-β-catenin signature pathway in TNBC is associated to the loss of PTEN. We identified differential expression of mRNAs in several key-components genes, and transcriptional target genes of the Wnt-β-catenin pathway (WP), including beta-catenin, FZD7, DVL1, MMP7, c-MYC, BIRC5, CD44, PPARD, c-MET, and NOTCH1 in FFPE tumors samples from TNBC patients of two independent cohorts. A similar differential upregulation of mRNA/protein for beta-catenin, the functional readout of WP, and for MMP7, a transcriptional target gene of beta-catenin was observed in TNBC cell line models. Genetic or pharmacological attenuation of beta-catenin by SiRNA or WP modulators (XAV939 and sulindac sulfide) and pharmacological mimicking of PTEN following LY294002 treatment downregulated MMP7 levels as well as enzymatic function of the secreted MMP7 in MMP7 positive PTEN-null TNBC cells. Patient data revealed that MMP7 mRNA was high in only a subpopulation of TNBC, and this subpopulation was characterized by a concurrent low expression of PTEN mRNA. In cell lines, a high expression of casein-zymograph-positive MMP7 was distinguished by an absence of functional PTEN. A similar inverse relationship between MMP7 and PTEN mRNA levels was observed in the PAM50 data set (a correlation coefficient of -0.54). The PAM50 subtype and outcome data revealed that the high MMP7 group had low pCR (25%) and High Rd (74%) in clinical stage T3 pathologic response in contrast to the high pCR (40%) and low residual disease (RD) (60%) of the low MMP7 group.

Genetic variation in candidate obesity genes ADRB2, ADRB3, GHRL, HSD11B1, IRS1, IRS2, and SHC1 and risk for breast cancer in the Cancer Prevention Study II

IntroductionObesity has consistently been associated with postmenopausal breast cancer risk. Proteins that are secreted by adipose tissue or are involved in regulating body mass may play a role in breast tumor development.MethodsWe conducted a nested case-control study among postmenopausal women from the American Cancer Society Cancer Prevention Study II Nutrition Cohort to determine whether genes associated with obesity increase risk for breast cancer. Tagging single nucleotide polymorphisms (SNPs) were selected to capture common variation across seven candidate genes that encode adipose-related proteins: ADRB2, ADRB3, GHRL, HSD11B1, IRS1, IRS2, and SHC1. Thirty-nine SNPs were genotyped in 648 cases and 659 controls. Logistic regression models were used to examine the association between each tagging SNP and risk for breast cancer while adjusting for matching factors and potential confounders. We also examined whether these SNPs were associated with measures of adult adiposity.ResultsTwo out of five tagging SNPs in HSD11B1 were associated with breast cancer (rs11807619, P = 0.006; rs932335, P = 0.0001). rs11807619 and rs932335 were highly correlated (r2 = 0.74) and, when modeled as a haplotype, only haplotypes containing the rs932335 C allele were associated with breast cancer. The rs932335 C allele was associated with a nearly twofold increased risk for breast cancer (odds ratio = 1.83, 95% confidence interval = 1.01–3.33 for C/C versus G/G). Three of the 11 SNPs for IRS2 were associated with breast cancer (rs4773082, P = 0.007; rs2289046, P = 0.016; rs754204, P = 0.03). When these three SNPs were examined as a haplotype, only the haplotype that included the G allele of rs2289046 was associated with breast cancer (odds ratio = 0.76, 95% confidence interval = 0.63–0.92 for TGC versus CAT). IRS2 rs2289046, rs754204, and rs12584136 were also associated with adult weight gain but only among cases. None of the other SNPs in any gene investigated were associated with breast cancer or adiposity.ConclusionOur findings suggest that these tagging SNPs in HSD11B1 and IRS2 mark regions of the genome that may harbor risk alleles for breast cancer, and these associations are probably independent of adiposity.