RASSF1 and cancer: The average time to clinical diagnosis of cancer since methylated alleles were detected in serum was 4.3 years for p16, 3.4 years for p15, and 4.4 years for RASSF1A. Since a series of genetic and epigenetic events occur during the long period, these genes seem to be potential epigenetic biomarkers for early detection of HCC or precancerous lesions non-invasively [4].