UGT1A polymorphisms associated with worse outcome in colorectal cancer patients treated with irinotecan-based chemotherapy

Purpose To investigate the association between UDP-glucuronosyltransferase ( UGT ) 1A polymorphisms and irinotecan-treatment efficacy in a Chinese population with metastatic colorectal cancer (mCRC). Methods The present study was based on a prospective multicenter trial of Chinese mCRC patients treated with irinotecan-based chemotherapy (NCT01282658, registered at http://www.clinicaltrials.gov ). Fifteen single-nucleotide polymorphisms (SNPs) in four UGT1A genes were selected for genotyping in 164 patients. Kaplan–Meier and Cox regression analyses were used to assess the association between potential signatures and survival outcome. Results We found that UGT1A1 * 28 variant genotype was significantly associated with decreased progression-free survival (PFS) [adjusted hazard ratio (HR), 1.803; 95% confidence interval (CI), 1.217–2.671] and overall survival (OS) (adjusted HR 1.979; 95% CI 1.267–3.091) compared with wild-type genotype. Patients carrying (TA)7 allele showed a median PFS of 7.5 (95% CI 5.5–9.6) months compared with 9.8 (95% CI 8.6–10.9) months for patients with wild-type genotype. Median OSs were 13.3 (95% CI 10.3–16.2), and 20.8 (95% CI 18.7–23.0) months for (TA)6/7 or (TA)7/7, and (TA)6/6 patients, respectively. Similarly but more significantly, the copy number of haplotype III (composed by rs3755321-T, rs3821242-C, rs4124874-G and rs3755319-C) constructed among the selected SNPs also correlated with survival outcome. Conclusions UGT1A polymorphisms are predictive of survival outcome of irinotecan-treated Chinese mCRC patients. After validation, UGT1A polymorphisms might be helpful in facilitating stratification of mCRC patients for individualized treatment options.