ABERRANT CRYPT FOCI IN PATIENTS WITH COLORECTAL-CANCER

Aberrant crypt foci (ACF) are clusters of abnormally large colonic cry pts identified on the mucosal surface of the human colon. They are tho ught to be preneoplastic lesions. The aim of the present study was to compare density (number of ACF per square cm of mucosal surface), cryp t multiplicity (number of crypts per ACF) and histology of ACF in colo nic resections of colorectal cancer patients resident in two Italian p rovinces with a twofold difference in colorectal cancer incidence rate s. Thirty-two and 26 colonic resections were collected after operation in Ragusa (Southern Italy) and Modena (Northern Italy), respectively, and fixed in 10% formalin. Mucosal layers were observed under a light microscope at 25x after staining with methylene blue. Density of ACF was significantly higher in Modena (median 0.101 ACF cm(-2)) than in R agusa (0.049, P= 0.001), whereas there was no difference in crypt mult iplicity. ACF were classified into three groups according to histologi cal features. ACF with mild alterations (hypertrophic ACF, 73%), ACF w ith hyperplasia (hyperplastic ACF, 17%) and ACF with dysplasia (microa denomas, 10%). The proportions of ACF in the three groups were similar in the two provinces, Density of ACF was higher and crypt multiplicit y lower proceeding from proximal to distal large bower. Microadenomas were observed only in the colon, whereas hyperplastic ACF were more fr equent in the rectum, In conclusion, density of ACF correlates with co lorectal cancer rates in two Italian provinces, and shows a positive g radient from proximal to distal large bowel. Histology of ACF suggests that they may be precursors of both hyperplastic and adenomatous poly ps. These data provide further evidence of the role of ACF in human co lorectal carcinogenesis.