WNT inhibitory factor 1 promoter hypermethylation is an early event during gallbladder cancer tumorigenesis that predicts poor survival

Gallbladder cancer (GBC) is the most common malignant tumor in the human biliary tract, but the lack of a marker for timely diagnosis leads to an extremely poor prognosis. In this study, we assessed CpG sites in the WIF-1 promoter using bisulfite sequencing PCR and methylation-specific PCR to detect methylation in gallbladder cancer and cholecystitis tissues. WIF-1 promoter methylation was present in 36 of 50 (72.0%) gallbladder cancers but only 5 of 20 (25.0%) cholecystitis tissues (P = 0.000 < 0.05), suggesting that WIF-1 promoter methylation might participate in the malignant transformation of cholecystitis into gallbladder cancer. WIF-1 methylation was negatively correlated with WIF-1 protein expression by immunohistochemistry, demonstrating that WIF-1 expression is downregulated by promoter hypermethylation. We analyzed the prognosis of 50 GBC patients with 5 years of follow-up. Univariate analysis revealed that patients with hypermethylated WIF-1 exhibited worse overall survival than those with hypomethylated WIF-1 (χ2 = 8.137, P = 0.004 < 0.05). Furthermore, multivariate analysis revealed that WIF-1 methylation was an independent prognostic factor for 5-year overall survival (P = 0.011). Therefore, WIF-1 methylation is a candidate as a marker for early gallbladder cancer diagnosis and prognosis.