The 12 enrolled articles consisted of 19 case–control studies with three FOXP3 polymorphisms (rs2280883 in four studies, rs3761548 in ten studies, and rs3761549 in five studies) and six cancer types (breast cancer in ten studies, colorectal cancer in one study, endometrial cancer in one study, hepatocellular in two studies, lung cancer in three studies, and thyroid cancer in two studies). Here, FOXP3 is linked to thyroid cancer.