CDO1 DNA methylation was quantified using quantitative TaqMan methylation specific PCR (Q-MSP) in 99 primary GBC patients together with the 78 corresponding non-tumor tissues and 26 benign gallbladder disease (including 7 patients with xanthogranulomatous cholecystitis) who underwent surgical resection between 1986 and 2014. The gene discussed is CDO1; the disease is neoplasm.