FAS and cancer: Furthermore, in these two genes, there are several functionally significant polymorphisms, such as the −670A>G and −1377G>A in the Fas promoter region, and the −844C>T in the FasL promoter region, because they might be associated with cancer risk, including cervical cancer [4]–[9], gastric cancer [10]–[15], breast cancer [16]–[21], lung cancer [22]–[25] and so on.