Apoptosis, cell proliferation and expression of Bcl-2 and Bax in gastric carcinomas: immunohistochemical and clinicopathological study

To clarify the relation between bcl-2 and bax protein (Bcl-2 and Bax) expression with regard to apoptosis and cell proliferation, 82 gastric carcinomas were immunohistochemically investigated. The significance of apoptosis for biological behaviour of the tumours was also examined. The apoptotic indices (AIs) were significantly lower in early-stage than in advanced-stage lesions (P<0.05), being positively correlated with the mitotic indices (MIs) (r=0.447, P<0.001). No association between either AIs or MIs and tumour size (diameter of intramural spreading) was noted. The AIs in the high Bcl-2-immunoreactive score group were significantly smaller than in either the low or the negative categories, whereas they were relatively elevated in the high Bax score group. In addition, an inverse correlation between Bcl-2 and Bax expression was revealed for both AIs and MIs. Although depth of tumour invasion and lymph node status were clearly associated with favourable outcome, no relation between survival rates and average values of either AIs or MIs, or immunoreactive scores for Bcl-2 and Bax was observed. These results indicate that in gastric carcinomas, apoptosis is closely associated with cell proliferation and expression of Bcl-2 and Bax, but appears likely to have no particular biological significance as a prognostic factor.