BCL-2 expression in human colorectal adenomas and carcinomas.

As BCL-2 oncoprotein has been implicated as a survival factor in a number of tissues, we examined colorectal tumour specimens and cell lines for BCL-2 expression. BCL-2 protein was expressed in 19/22 adenocarcinomas and 12/13 adenomas. 6/9 carcinoma cell lines and 7/8 adenoma cell lines were also BCL-2 positive. BCL-2 expression was retained in metastases to the regional lymph nodes (3/3 specimens) and in the cell line SW620, derived from a lymph node metastasis. These studies suggest a role for BCL-2 in promoting cell survival of benign and malignant colorectal tumours and that BCL-2 deregulation may be a relatively early event in colorectal carcinogenesis. The retention of BCL-2 expression in the carcinomas and lymph node metastases may explain the resistance of colorectal tumours to chemotherapeutic treatment.