CDKN2A and cancer: Considering the complex network in colon tumors, with communication between cancer cells and surrounding stromal cells, there are still some genes or group of genes that are frequently occurring as targets for these anti-cancer substances, e.g., POLR1C (transcription regulation), CDKN2A and cyclins (cell cycle), MHC class II genes (immune system), MAPKs, PRKC, BMPs and FGFR (signal transduction), integrins (cell adhesion), CEACAM 5 (oncogene) and histones (cell cycle control).