For example, two negative results were described in the following sentences: “study does not support a role of COX2 and UGT1A6 genetic variations in the development of colon cancer”12 and “neither genetic variation nor allele-specific expression at TGFBR1 is likely to be a major colorectal cancer risk factor”13. This evidence concerns the gene TGFBR1 and colorectal cancer.