Recently, studies have explored the association of an important and frequent polymorphism, namely -93G>A (rs1800734), which is located in the core promoter region of hMLH1, with susceptibility to developing various human malignancies, including tobacco-related oral carcinoma [18], lung cancer [19], colorectal cancer [20] and papillary thyroid carcinoma (PTC) [21]. This evidence concerns the gene MLH1 and colorectal cancer.