Kubo, Michiaki

Abstract Background: Controversy exists regarding the association between CYP2D6 enzyme activity and tamoxifen effectiveness in the adjuvant treatment of invasive breast cancer; however, this association in the primary prevention of breast cancer is unknown. Methods: We conducted a nested case–control study in the context of the NSABP P1 and P2 prevention trials to determine the impact of CYP2D6 genotype, CYP2D6 inhibitor use, and metabolizer status (CYP2D6 genotype combined with CYP2D6 inhibitor use), on breast cancer events. Women who developed breast cancer (both noninvasive and invasive) while on 5 years of selective estrogen receptor modulators therapy (cases) were matched to controls free of breast cancer. Comprehensive CYP2D6 genotyping was conducted for alleles associated with absent (*3, *4, *5, and *6), reduced (*10, *17, and *41), and increased (*1XN and *2XN) enzyme activity. Information regarding the use of CYP2D6 inhibitors was recorded. Results: A total of 591 cases were matched to 1,126 controls and DNA was genotyped in more than 97%. In patients treated with tamoxifen, there was no association of CYP2D6 genotype [OR (extensive/poor metabolizer): 0.90; 95% CI: 0.46–1.74, P = 0.74), use of a potent CYP2D6 inhibitor (OR 0.92; 95% CI: 0.575–1.486), or CYP2D6 metabolizer status (OR 1.03; 95% CI: 0.669–1.607) with breast cancer occurrence. Likewise, there was no association between any CYP2D6 metabolism parameter with breast cancer events in raloxifene-treated patients. Conclusion: In the NSABP P1 and P2 clinical trials, alterations in CYP2D6 metabolism are not associated with either tamoxifen or raloxifene efficacy. Clin Cancer Res; 17(21); 6944–51. ©2011 AACR.

Abstract Background: The third-generation aromatase inhibitors (AIs) are established adjuvant therapy for postmenopausal women with early stage breast cancer. Musculoskeletal adverse events (MS AE) have become increasingly recognized as an issue for many women receiving AIs resulting in decreased quality of life and, in some instances, discontinuation of the AI. MA.27 is an ongoing randomized clinical trial comparing anastrozole with exemestane that accrued 7576 patients (pts), including 6827 from North America, about 79% of whom provided DNA and consent for genetic testing. A review of withdrawals related to adverse events revealed that the most common cause was MS AE. The hypothesis for our study was that a genome-wide association (GWA) case control study would identify single nucleotide polymorphisms (SNPs) associated with MS AE.Methods: Cases were defined as pts with grade 3 or 4 MS AE (NCI CTCAE v3.0) or who went off treatment for any grade MS AE within the first 2 years and were matched to 2 controls based on treatment arm, length of follow-up, prior chemotherapy, age and prior celecoxib (at least 3 months prior to MS AE). The study was restricted to the 94% of pts self-identified as Caucasian. Genotyping was performed with the Illumina Human610-Quad. Genotype quality control prior to analysis required call rates ≥98%. Eigenstrat analyses were performed to control for population stratification.Results: The GWA study included 293 cases and 586 controls with 6 pts (0.7%) (4 cases, 2 controls) excluded for call rates <98%. 551,358 SNPs were used in the analyses after removing 29,439 for a minor allele frequency <1% and 82 with Hardy Weinberg Equilibrium p-values <10-6. Eigenvectors did not impact the results when used as covariates. Four SNPs with the lowest p-values (3.3-8.2 x 10-6, Armitage test), 3 in high LD (r2>.8) on chromosome (ch) 14 (rs7158782, rs7159713, rs2369049) and 1 on the X ch (rs6637820) were identified. The gene closest (4000-7000 bp) to the 3 SNPs on ch 14 was T-Cell Leukemia 1A (TCL1A), encoding a protein known to augment AKT kinase activity. Expression array data from lymphoblastoid cell lines from 300 subjects of 3 ethnicities revealed that all 3 SNPs were associated with decreased TCL1A expression after adjusting for ethnicity using 2 probe sets (p=0.006 to 0.03). Electromobility shift assay (EMSA) showed that 2 of these SNPs (rs7158782, rs7159713) displayed a shift and the former SNP showed substantially less binding for variant than wild type. The gene closest to the X ch SNP was Immunoglobulin Superfamily 1 (IGSF1), but EMSA did not show a shift for this SNP.Conclusions: MS AEs represent a major impediment to optimal use of AIs in women with breast cancer and this GWA study identified SNPs on ch 14 that provide a focus for further research to identify pts at risk for, and means to ameliorate, this adverse event.(Supported in part by NIH grants U01GM61388, U01GM63173, P50CA116201 and U10CA77202) Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 15.

Purpose We performed a case-control genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with musculoskeletal adverse events (MS-AEs) in women treated with aromatase inhibitors (AIs) for early breast cancer. Patients and Methods A nested case-control design was used to select patients enrolled onto the MA.27 phase III trial comparing anastrozole with exemestane. Cases were matched to two controls and were defined as patients with grade 3 or 4 MS-AEs (according to the National Cancer Institute's Common Terminology Criteria for Adverse Events v3.0) or those who discontinued treatment for any grade of MS-AE within the first 2 years. Genotyping was performed with the Illumina Human610-Quad BeadChip. Results The GWAS included 293 cases and 585 controls. A total of 551,358 SNPs were analyzed, followed by imputation and fine mapping of a region of interest on chromosome 14. Four SNPs on chromosome 14 had the lowest P values (2.23E-06 to 6.67E-07). T-cell leukemia 1A (TCL1A) was the gene closest (926-7000 bp) to the four SNPs. Functional genomic studies revealed that one of these SNPs (rs11849538) created an estrogen response element and that TCL1A expression was estrogen dependent, was associated with the variant SNP genotypes in estradiol-treated lymphoblastoid cells transfected with estrogen receptor alpha and was directly related to interleukin 17 receptor A (IL17RA) expression. Conclusion This GWAS identified SNPs associated with MS-AEs in women treated with AIs and with a gene (TCL1A) which, in turn, was related to a cytokine (IL17). These findings provide a focus for further research to identify patients at risk for MS-AEs and to explore the mechanisms for these adverse events.