Effects of SLC31A1 and ATP7B polymorphisms on platinum resistance in patients with esophageal squamous cell carcinoma receiving neoadjuvant chemoradiotherapy

The relationship between the SLC31A1 (protein: copper transporter 1) rs10981694 A > C and ATP7B (protein: P-type adenosine triphosphatase 7B) rs9535828 A > G polymorphisms on the overall survival and disease-free survival of 104 Japanese patients with esophageal squamous cell carcinoma (ESCC) receiving neoadjuvant chemoradiotherapy (CRT) was investigated. Chemotherapy consisted of protracted infusion of 5-fluoracil (800 mg/m²/day) on days 1–5 and cisplatin or nedaplatin (80 mg/m²/day) on day 1. The median (range) follow-up was 47 (6–127) months. The 5-year overall and disease-free survival rates were 71.2% and 60.6%, respectively. The 5-year overall survival rate was significantly higher in patients with the SLC31A1 rs10981694 C allele compared with the rs10981694 A/A genotype (91.7% vs. 65.0%, P = 0.018). The 5-year disease-free survival rate was significantly higher in patients with the SLC31A1 rs10981694 C allele compared with the rs10981694 A/A genotype (79.2% vs. 55.0%, P = 0.043). In addition, univariate and multivariate analyses showed the SLC31A1 rs10981694 A > C polymorphism to be a significant prognostic factor affecting 5-year overall survival after neoadjuvant CRT. However, the overall and disease-free survival rates after surgery did not differ significantly among the ATP7B rs9535828 genotypes. In conclusion, only the SLC31A1 rs10981694 A/A genotype was an independent predictor of a poorer 5-year overall survival. Therefore, in neoadjuvant CRT for ESCC patients, the effect of platinum was affected by the SLC31A1 rs10981694 A > C polymorphism. The presence of this polymorphism should be considered when devising neoadjuvant CRT regimens or treatment strategies for ESCC.