The studies have shown that metformin exerts antitumor effects against different types of cancer (e.g., breast, colon, liver, prostate, and kidney cancer) (28–30) primarily by reducing glycemia to cutoff the phosphoinositide 3-kinase (PI3K)/mitogen-activated protein kinase (MAPK) pathway or by activating the AMPK pathway (31). This evidence concerns the gene PIK3CA and kidney cancer.