Expression of the ets-1 proto-oncogene in human colorectal carcinoma

The proto-oncogene, ets-1, is a transcription factor known to control the e xpression of a number of genes involved in extracellular matrix remodeling and has been postulated to play a role in cell migration and tumor invasion . To elucidate the involvement of ets-1 in human colorectal carcinomas, we examined 41 cases of colorectal adenoma and 122 cases of colorectal carcino ma by immunohistochemistry and compared the degree of Ets-1 expression with the depth of carcinoma invasion. In adenomas, 12 of 41 cases (29.3%) showe d immunopositivity for Ets-1, 12 of 27 cases (44.4%) of adenoma with high g rade dysplasia showed immunopositivity for Ets-1. However, there was no pos itive case in low or moderate dysplasia of adenoma, In contrast, 103 of 122 cases (84.4%) of colorectal adenocarcinoma showed inmunoreactivity for Ets -1 in the carcinoma cells themselves. We investigated the relationship betw een pathological features in colorectal carcinoma and Ets-1 immunoreactivit y of the tumor cells. Among the 122 cases of invasive carcinomas, Ets-l imm unoreactivity was significantly correlated with the depth grading of tumor invasion (P < .0001), the presence of lymph node metastasis (P < .05), lymp hatic invasion (P < .01) and venous invasion (P < .05), However, Ets-1 expr ession did not correlate with histological differentiation. In situ hybridi zation also confirmed the presence of ets-1 mRNA in colorectal carcinomas. Expression of ets-1 mRNA was also detected in two of three human colorectal carcinoma tissues and in four of six different kinds of carcinoma cell lin es by the reverse transcription polymerase chain reaction method. These fin dings suggest that the expression of Ets-1 is one of the important factors related to carcinogenesis and/or tumor invasion of colorectal carcinoma.