H6PD and colorectal cancer: A retrospective observational study in ~4,000 patients that underwent colonoscopy with a 10 years follow-up from Sardinia region (Italy), where G6PDH-deficiency prevalence ranges between 12 and 24% and is often caused by the G6PDHC563T variant, shows that G6PDH-deficiency is associated with reduced colorectal cancer risk (5, 6).