Correspondence between flat aberrant crypt foci and mucin-depleted foci in rodent coloncarcinogenesis.

Background: Flat Aberrant Crypt Foci (flat ACF) and Mucin Depleted Foci (MDF) are preneoplastic lesions described in the unsectioned colon of carcinogen-treated rodents. Flat ACF are identified by methylene blue (MB) and MDF by high iron diamine-alcian blue (HID-AB) staining. We explored the correspondence between flat ACF and MDF, scored in the same whole colon preparations of Min mice treated with azoxymethane and of F344 rats treated with 1,2-dimethylhydrazine. Materials and Methods: The position of each flat ACF was recorded on a digitally constructed photographic map of MB-stained colon. The same colons were then stained with HID-AB for MDF determination, and the position of each MDF was compared with that of flat ACF. Results: The fraction of coincident lesions, identified as both flat ACF and MDF with the two staining methods, was 57% and 42%, in Min mice and F344 rats, respectively. Flat ACF or MDF not coincident with the two staining methods were either undetectable or ACF with one of the two methods. Conclusions: Flat ACF and MDF show considerable, but not total, overlap