Class II HLA antigen expression in familial polyposis coli is related to the degree of dysplasia.

Class II HLA antigen expression was studied in 30 polyps from 3 patients who were diagnosed with familial polyposis coli. The highest levels of this expression were associated with the most severe grades of dysplasia (p less than 0.00001), the sequence of positivity being HLA-DR greater than DQ greater than DP. No association was observed between the expression of these antigens and the presence of a specific inflammatory leukocytic infiltrate. Our results imply that HLA class II molecule expression is somehow related to malignant transformation in familial polyposis coli in accordance with the adenoma-dysplastic adenoma-adenocarcinoma sequence. Thus these antigens may be useful markers to tumoral progression.