The genes distinguishing tumours from matched normal mucosa were SFRP1, SFRP2, MYOD and MINT31, whereas those distinguishing the morphologically normal mucosa of cancer patients from that of non-cancer (neoplasia-free+polyp) patients were HPP1, APC, p16, SFRP4, ESR1 and WIF1, although SFRP4, SFRP5 and WIF1 could distinguish the normal mucosa of polyp patients from those without neoplasia. Here, CDKN2A is linked to polyp.