HUMAN COLORECTAL CARCINOMAS EXPRESS HIGH-LEVELS OF HIGH-MOBILITY GROUP HMGI(Y) PROTEINS

A correlation has previously been demonstrated between the presence of the three HMGI proteins (HMGI, HMGY, and HMGI-C) and the expression o f a highly malignant phenotype in epithelial and fibroblastic rat thyr oid cells; this being subsequently extended to experimental thyroid, l ung, prostate, mammary, and skin carcinomas. Recently, we have demonst rated that expression of HMGI and HMGY proteins, coded for by the HMGI (Y) gene, is associated with the malignant phenotype of human thyroid neoplasias. Here, we show that HMGI(Y) gene expression is present both at the RNA and protein level in human colorectal carcinoma fell lines and tissues examined in this study, Conversely, no HMGI(Y) proteins w ere detected in normal intestinal mucosa. Therefore, these results sug gest an involvement of HMGI and HMGY proteins overexpression in colore ctal tumorigenesis.