In the stratified analysis based on cancer types, significant associations were observed between NQO1C609T polymorphism and GC (OR = 1.38, 95% CI = 1.11-1.72, p = 0.003) and CRC (OR = 1.18, 95% CI = 1.06-1.30, p = 0.001), but not with EC (OR = 1.16, 95% CI = 0.99-1.35, p = 0.06).
Overall, a significant association was found between the NQO1C609T variant and esophageal cancer under a recessive model (OR = 1.647; 95% CI = 1.233-2.200).
Meta analysis of NQO1 polymorphism also indicated null association of the polymorphism with EC overall or with cancer cases stratified by tumor histopathology/ethnicity.