FAS and esophageal squamous cell carcinoma: FAS -670A > G and FASLG -844 T/C polymorphisms have been previously associated with an increased risk of HNC [52], gynecological cancer [53] and esophageal squamous cell cancer [54], whereas FAS -670A > G has been also associated with an increased risk of recurrence and death in epithelial ovarian cancer patients [53].