SFRP4 and polyp: 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.