Apoptosis and apoptosis-related proteins (Fas, Fas ligand, Blc-2, p53) in lymphoid elements of human ovarian tumors

Different types of lymphocytes have different roles in tumor suppression Th us. their expression of apoptosis-related proteins (ARP - Fas and Fas ligan d, bcl-2, p53) in lymphocytes and their apoptosis were analyzed immunohisto chemically in ovarian tumors of different grades. Ovaries without oncologic disorders had few lymphocytes, mainly T cells, and no ARP. Benign cysts pr esented features of weak immune reaction: small lymphoid infiltration and f ew lymphocytes. The ARP were present in 13.7% to 23.5% of the lymphocytes, and apoptosis was rare. In borderline tumors, expansion of lymphoid infiltr ates and increased density of lymphocytes resulted in a tenfold rise in tot al lymphocytes, reflecting intensification of the immune response. Most lym phocytes were T cells (92%) predominated by CD8+ cells that were in direct contact with tumor epithelial cells. ARP species were found in 47% to 65% o f the lymphocytes, and apoptosis in 2.2%. In carcinomas with ligh lymphoid infiltration, lymphocytes were 2.5 times more abundant, and the apoptotic i ndex as well as the number of CD20+ and CD25+ lymphocytes rose sharply, whe reas bcl-2 positive lymphocytes decreased to 8% of their number in borderli ne tumors. In carcinomas with low lymphoid infiltration, the total lymphocy te count decreased eightfold compared to carcinomas with high lymphoid infi ltration, reflecting the deep subcompensation of the lymphoid system. Few p 53-positive lymphocytes were found in the carcinomas. In conclusion, we fou nd a positive cor relation between apoptosis and the numbers of CD4+ or CD8 + lymphocytes in epithelial ovarian tumors. This correlation could reflect the antitumor activity of T cells. However, the high expression of ARP stud ied by immune cells at the vicinity of the tumor ARP reveals the lymphoid v ulnerability to apoptosis, resulting in devastation of the lymphoid tissue: and consequently in tumor progression.