ABERRANT CRYPT FOCI IN HUMAN COLON CARCINOGENESIS

We developed a procedure for the endoscopic visualization in humans of aberrant crypt foci (ACF), preneoplastic lesions of the colon mucosa, and we determined the frequency of ACF in resected sections of human colon. For the endoscopy we studied 12 consenting adults (6 controls a nd 6 colon cancer cases) by dying colon mucosa with 0.5% methylene blu e and searching ACF with a magnifying endoscope. ACF of varying dimens ions were visualized in all subjects. We also studied colon surgical s pecimens from patients with colon cancer or diverticulitis. After stai ning the mucosa with 2% methylene blue, we found approximately the sam e density of ACF in the colon mucosa of the patients with colon cancer as in that of patients with diverticulitis (ACF/cm(2) were 0.124 +/- 0.143 [N = 14] and 0.108 +/- 0.210 [N = 4], respectively [mean +/- SD] ). In conclusion, the visualization of ACF with methylene blue in huma ns does not identify groups at low and high risk of colon cancer.