Expression of bcl-2 and apoptotic DNA fragmentation in human endometrial adenocarcinoma cells

Immunohistochemical detection of bcl-2 products and in situ estimation of DNA fragmentation during apoptosis by the nick and labelling method were performed to establish any correlation between these two apparently opposing processes in human solid tumors. Serial sections, one micrometer in thickness, from formalin-fixed and paraffin-embedded tissues of 10 cases of human endometrial adenocarcinoma were examined using the two techniques. A significant fraction of carcinoma cells were found to be stained by both methods, although there existed a general tendency for bcl-2 expression to be negatively correlated with DNA fragmentation in carcinoma tissue. The results thus suggest that bcl-2 expression does not always block apoptosis, and that simultaneous application of bcl-2 immunostaining and DNA nick end labeling is useful for showing the complex nature of apoptosis in histologic slides, especially in gynecological cancers.