Objective: To investigate the role of Fas/Fas ligand (FasL) in tum orgenesis, immune escape, counterattack in colonic cancer.
Methods: Fas and FasL were measured by immunohitochemistry in 52 colon cancer, 27 adenomas, 28 ulcerative colitis (UC), 30 normal colon tissues and 23 lymph node metastases of colon cancer. In different FasL expression regions, the apoptosis of tumor cells was detected by TUNEL.
Results: (1) The expression rate of Fas was lowest in colon cancer tissue. It was lower than that in adenomas and UC, while it was highest in normal tissue. Compare of Fas, FasL was highest in colon cancer tissue, lowest in the normal tissue. The FasL in adenomas and UC were higher than that in the normal tissue. (2)Expression of Fas/FasL was not correlated with the typ e of tumor histology, but it was correlated with Dukes'stage, tumor differentiation and lymph node metastasis.(3) In the same tumor tissue, FasL expression was not even. Apoptotic rate of tumor cells was higher in FasL positive region(n = 25)(81.2%) than that in FasL negative region(n = 25)(47.4%)(P < 0.01). (4) FasL was strong positive in all 23 lymph node metastases of large intestine cancer, and more than 75% tumor cells were FasL positive in each tissue.
Conclusion: Fas/FasL play an important role in tumorgenesis, immune escape, counterattack in colon cancer.