[Expression of MIB-1/KI-67 and bcl-2 in gastric carcinoma. Relationship with clinico-pathological factors]

Neoplastic development partly depends on a balance between cellular proliferative activity and the eventual suppression of the mechanism of apoptosis. Proliferative activity can be estimated by quantification of KI-67 antigen that appears during phases G1, S, G2 and M of the cellular cycle, whereas apoptosis is shown by the expression of the bcl-2 protein. In this study the expression of KI-67 and bcl-2 antigens was examined in a series of 97 gastric adenocarcinomas, to find out their relations with different clinical and pathological factors. The results showed that the expression of KI-67 was only associated to histological grade and did not have any prognostic significance. On the other hand, there was a better 5 year survival rate when invasion did not go beyond the muscularis propria, there were no lymph node metastases, in the woman and when tumors were located in the antrum. bcl-2 protein was surprisingly negative in all cases albeit of previous descriptions of overexpression of this protein in cases of gastric dysplasia. It is postulated that expression of bcl-2 could appear at an early stage of gastric carcinogenesis and that only a small proportion of malignant tumors would maintain that overexpression.