Promoter methylation, which is an epigenetic change, is the predominant mechanism of RASSF1A gene inactivation, and has been recognized in many human solid tumors, including non-small cell lung carcinoma (NSCLC) [15], [16], [17], breast carcinoma [10], [18], [19] and colorectal carcinoma [20], [21]; thus, RASSF1A promoter methylation may be a prognostic indicator in such tumors. This evidence concerns the gene RASSF1 and colorectal carcinoma.