G6PD and gastric cancer: For example, glucose‐6‐phosphate dehydrogenase (G6PD), which participates in the pentose phosphate pathway, was overexpressed in gastric cancer tissues compared to normal stomach mucosa tissues, and its level was associated with tumor size, depth of invasion, lymph node metastasis, distant metastasis, TNM stage, and survival rate (Wang et al., 2012), indicating that G6PD expression level was an independent prognostic factor for gastric cancer patients after radical resection.