Abstract
BACKGROUND: The finding was recently reported of clusters of colonic crypts lined with indigenous normal epithelium displaying irregular shapes underneath the adenomatous glands of conventional (tubular or villous) adenomas. These abnormal crypts were named non-dysplastic corrupted colonic crypts (NDCs). This study explored the characteristics of cell proliferation in NDCs present in a cohort of conventional adenomas. MATERIALS AND METHODS: Sections from six conventional adenomas were challenged with the proliferation marker Ki-67 (MIB1). MIB+ proliferating clusters were regarded as those exhibiting two or more adjoining MIB+ cells. RESULTS: A total of 46 (range=1-18) NDCs were found underneath the six conventional adenomas. Out of the 46 NDCs, two exhibited only one proliferative cluster/crypt, 14 NDCs two clusters/crypt, 14 three clusters/crypt and the remaining 16 NDCs more than four distinct clusters/crypt. CONCLUSION: This preliminary study showed, evidently for the first time, that multiple, apparently haphazardly distributed clusters of proliferating cells are present in NDCs. Since the Ki-67 proliferation marker only labels progenitor daughter cells generated by stem cells, each MIB+ cluster in each NDC must have been produced by a single stem cell. Consequently, individual NDCs may harbor several stem cells, a deduction that is in concert with recent studies showing that in the normal human colon, the number of stem cells per crypt is of the order of five to six, or about 5% of the cell population of a single crypt.