Expression of apoptosis and apoptosis-related proteins in microvessels of human ovarian epithelial tumors

We performed an immunohistochemical analysis of apoptosis and the expressio n of apoptosis-related proteins (ARP) such as Fas and Fas ligand (FasL), bc l-2 find p53 in human ovarian epithelial tumors. Fas and Fast were abundant in endothelial cells of microvessels, and were observed, at times, in the myocytes of small arteries and veins, in parietal ol in obstructive thrombi and fibroblasts. Apoptosis was also noticed in the endothelial cells of ca pillaries and sinuses. The expression of bcl-2 or p53 was rare. We found th at the progression of tumor development was accompanied by considerable cha nges in the microvessels of ovarian tumors. These changes al e probably rel ated to the effect of ARP that are expressed by tumor epithelial cells, lym phocytes and macrophages. We suggest that the ARP are released as a result of necrosis of these cells and ai e taken up by cells of microvessels and b y the cellular remnants of blood clots. The effect of tumors on the microva sculature can be regarded as an angiopathy that results in necrosis and hem orrhage within the tumoral tissue and enhances the progression of the malig nancy.