Bcl-2 protein expression and gut neurohormonal polypeptide/amine production in colorectal carcinomas and tumor-neighboring mucosa, which closely correlate to the occurrence of tumor

To clarify whether advanced colorectal carcinomas and tumor-neighboring muc osa simultaneously produce both Bcl-2 protein and gut neurohormonal polypep tides andior amines, and the interrelationship of these phenomenon, we stud ied retrospective analysis of Bcl-2 protein production and neuroendocrine c haracteristics in 52 cases of advanced colorectal carcinoma and surrounding mucosa. All of the tumor-neighboring mucosa presented hyperplasia. The rat es of enhanced immunoreactivity of the tumor-neighboring mucosa and of posi tive immunoreactivity of the carcinomas against human Bcl-2 protein and aga inst human vasoactive intestinal polypeptide, pancreatic polypeptide and so matostatin were 78.8% and 94.2%, 82.7% and 59.6%, 78.8% and 67.3%, and 88.5 % and 84.6% respectively. Double immunostaining for Bcl-2 protein and each peptide hormone revealed simultaneous expression. In contrast, that of tumo r-neighboring mucosa and carcinomas to serotonin and chromogranin-A and to argyrophilia were 11.5% and 1.9%, 32.7% and 17.3%, and 26.9% and 21.2%, res pectively. We concluded that tumor-neighboring crypt cells displayed not on ly hyperplasia but also neuroendocrine characteristics and that enhanced Bc l-2 protein immunoreactivity correlated with tumor occurrence in the wall o f the colorectum. The production of Bcl-2 protein by tumor cells and tumor- neighboring crypt cells indicates that the bcl-2 protooncogene may act not only as an inhibitor of apoptosis but also as an inducer of neuroendocrine differentiation from the latent characteristics of the endodermal stem cell .