CDKN2A and cancer: We determined the mean methylation of the promoter regions in APC (NC_000084.6), CDKN2A (NC_000009.12), and EFNA5 (NC_000005.10), a cis-regulatory region in RAD9A intron 2 (NC_000011.10), and a mutation hotspot in TP53 exon 6 (NC_000017.11) in 20 primary fibroblast cell lines of cancer-free controls 0N and matched patients 1N and 2N (Figure 1A-E(Fig. 1)).