Objectives: The objective of the study is to investigate whether multiple chemotherapeutic agent-related genetic polymorphisms are associated with the clinical outcomes of Taiwanese metastatic colorectal cancers (mCRC) patients treated with the first-line FOLFOX-4 chemotherapy.
Methods: Consecutive mCRC patients were prospectively enrolled into this study. Peripheral blood samples were used for genotyping of polymorphisms in MTHFR, DPD, GSTP1, MDR1, TYMS, ERCC1, XRCC1, and ERCC2 genes by polymerase chain reaction-restriction fragment length polymorphism technique and DNA sequencing. The primary end point of the study was to investigate the association of each genetic polymorphism with progression-free survival and overall survival (OS).
Results: Favorable genotypes from polymorphisms in ERCC1 codon 118C/C [hazard ratio (HR)=0.061, 95% confidence interval (CI): 0.014-0.274, P<0.001] and XRCC1 codon 399G/G (HR=0.306, 95% CI: 0.103-0.905, P=0.032) that are associated with progression-free survival were identified. Furthermore, ERCC1 codon 118C/C (HR=0.065, 95% CI: 0.011-0.377, P=0.002) and XRCC1 codon 399G/G (HR=0.152, 95% CI: 0.041-0.568, P=0.005) were significantly associated with favorable OS. Combining ERCC1 and XRCC1 genetic polymorphisms, patients with both favorable genotypes of ERCC1 codon 118C/C and XRCC1 codon 399G/G were associated with the better OS than those with one or without any favorable genotypes (P<0.001).
Conclusion: The genetic polymorphisms of ERCC1 and XRCC1 may be useful in predicting clinical outcome in Taiwanese mCRC patients treated with FOLFOX-4. However, further prospective studies will be needed for the potential clinical implication.