CDA and MTHFR polymorphisms are associated with clinical outcomes in gastroenteric cancer patients treated with capecitabine-based chemotherapy.

<bold>Purpose: </bold>The impact of pharmacogenetics on predicting survival in gastroenteric cancer remains unclear.<bold>Methods: </bold>We tested 322 consecutive patients treated with capecitabine-based chemotherapy for CDA and MTHFR polymorphisms.<bold>Results: </bold>Patients who carried the CDA 79 A>C (rs2072671) CC genotype showed significantly shorter progression-free survival (PFS) comparing with A-allele (P = 0.008). A significant better PFS was found in the patients with 451 A>G (rs532545) G-allele (P = 0.002) and 92 C>T (rs602950) T-allele (P = 0.002). In addition, a shorter PFS was also observed in patients with MTHFR 1298 A>C (rs1801131) CC genotype than the patients with AC or AA genotype after capecitabine-based chemotherapy (P = 0.002). Furthermore, the colon, female, or elder (> 65 years old) patients with MTHFR 1298 A>C CC genotype had poorer PFS than A-allele. Moreover, CDA 451 A>G was independent predictors of chemotherapy-induced toxicity in colon patients. Multivariate Cox regression analysis demonstrated that the CDA 79 A>C CC, 451 A>G AA, 92 C>T CC, and MTHFR 1298 A>C CC were predictive of shorter PFS in gastroenteric cancer patients.<bold>Conclusions: </bold>The results reminded us those gastroenteric cancer patients with CDA 79 A>C CC, 451 A>G AA, 92 C>T CC, or MTHFR 1298 A>C CC genotype are not likely to benefit from the therapy of capecitabine-based chemotherapy. [ABSTRACT FROM AUTHOR]