Loss of heterozygosity of XAF1 gene has been reported in human colorectal cancers [22] and promoter CpG hypermethylation of XAF1 has been found in several human malignant tumors such as gastric [18, 23], colon [23], melanoma [24] and urogenital tumor [25-27]. Here, XAF1 is linked to colorectal cancer.