APC and colonic neoplasm: To evaluate changes in NEC populations during the stepwise pathologic progression to colon cancer, we examined the above markers (Fig 1A and 1B) in neoplastic colon tissues with varying APC genotypes: normal-appearing FAP crypts (heterozygous mutant APC); adenomatous FAP crypts (homozygous mutant APC); colon carcinomas (homozygous mutant APC & other mutations).