Colonic aberrant crypts in azoxymethane-treated F344 rats have decreased hexosaminidase activity

Aberrant crypts, identified with methylene blue staining of unsectioned colon from carcinogen-treated rats on the basis of their increased size, were examined for the altered expression of hexosaminidase activity. Previously we identified enzyme-altered foci with normal morphology in sections of colon from carcinogen-treated rats. A reduction of histochemically demonstrable hexosaminidase activity was the most consistent marker for these foci. Aberrant crypts, marked with permanent ink and embedded in methacrylate, had a marked decrease of hexosaminidase activity compared to the adjacent, normal crypts. Hexosaminidase may be a marker that will aid in the identification of the molecular basis of colon cancer in a manner similar to that of esterase D and retinoblastoma.