CDKN2A and neoplasm: Although the concepts involved in cell cycle and DNA repair activity were shown to be depleted in differential methylation, indicating fewer genes involved in this concept are affected via DNA methylation change than by chance, certain crucial regulator genes such as APC, CDKN2A, and CDKN2B[21,28,29] were still shown to be differentially methylated to a great extent in multiple tumor types.