Impact of Gene Polymorphisms on Clinical Outcome for Stage IV Melanoma Patients Treated with Biochemotherapy: An Exploratory Study

Abstract

Biochemotherapy can achieve high response rates in advanced melanoma, but the factors that influence regression and survival remain unknown. The present exploratory study tested the hypothesis that cytokine gene polymorphisms predict clinical outcome in stage IV melanoma patients treated with biochemotherapy. Ninety patients with stage IV melanoma were treated with biochemotherapy, including cisplatin, vinblastine, and dacarbazine combined with interleukin (IL)-2 and IFN-alpha either with or without tamoxifen. Cytokine gene polymorphisms for IFN-gamma (+874A-->T) and IL-10 (-1082G-->A) were assessed. X-ray repair cross-complementing gene 1 (XRCC1; Arg399Gln), xeroderma pigmentosum complementary group D (XPD; Lys751Gln), and excision repair cross-complementing gene 1 (ERCC1; codon 118) DNA repair polymorphisms were also determined. IFN-gamma (+874A-->T) gene polymorphism was statistically significantly associated with response (P = 0.001), progression-free survival (P = 0.0012), and overall survival (P < 0.001), whereas the IL-10 polymorphism was marginally associated with response (P = 0.03) and overall survival (P = 0.065). Multivariate analysis revealed that IFN-gamma (+874A-->T) independently predicted overall survival (P = 0.003). The ERCC1 polymorphism was weakly associated with overall survival (P = 0.045). Combining polymorphisms for IFN-gamma, IL-10, and ERCC1 stratified patients into four distinct groups with significantly different clinical outcome (P < 0.001), so that patients with more "favorable" polymorphisms had a better outcome. Cytokine gene polymorphisms predicted clinical outcome for advanced melanoma patients who received biochemotherapy. The combined effects of multiple genetic polymorphisms may provide more accurate prognostic information. Additional independent studies are needed to confirm these pilot findings.