Carcinoembryonic antigen in human colonic aberrant crypt foci.

BACKGROUND/AIMS: Aberrant crypt foci are putative preneoplastic lesions that, by definition, are identified microscopically in whole-mount preparations of colonic mucosa. Because the identification of hexosaminidase as a marker for rat aberrant crypt foci in histological sections facilitated their characterization, a similar marker for human foci in histological sections was sought.

METHODS

Human aberrant crypt foci were marked in whole-mount preparations, embedded in paraffin, and evaluated for their expression of carcinoembryonic antigen with two monoclonal antibodies.

RESULTS

Elevated expression of carcinoembryonic antigen was detected in 39 of 42 (93%) aberrant crypt foci from 15 patients. The expression of carcinoembryonic antigen assisted in the evaluation of longitudinal sections of foci, where dysplasia is more readily detected in these small lesions. The expression of carcinoembryonic antigen was related to the sizes of the foci (P = 0.0085, generalized Fisher's Exact Test) but not to the presence or degree of dysplasia.

CONCLUSIONS

The overexpression of immunohistochemically demonstrable carcinoembryonic antigen is, to date, the only described alteration in most of these putative precursors of human colon cancer that differs from the expression in contiguous, normal crypts at the histological level and thus facilitates the identification of aberrant crypts in histological sections for further characterization.