大肠癌浸润淋巴细胞Fas配基表达与癌细胞凋亡的关系

目的　研究结肠直肠癌浸润淋巴细胞Fas配基 (FasL)表达与癌细胞凋亡的关系。　方法　用免疫组化方法检测 86例结肠直肠癌及切缘正常大肠组织的Fas蛋白、FasL的表达 ;用TdT酶介导的DNA3′ OH末端 缺口染色方法检测癌细胞的调亡指数 ,并分析浸润淋巴细胞FasL表达与癌细胞凋亡指数的关系。　结果　 86例结肠直肠癌组织呈Fas蛋白染色阳性 5 3例 (6 1 6 % ) ,正常大肠组织则未见染色 ,癌组织旁浸润淋巴细胞FasL染色阳性 6 9例 (80 2 % )。癌组织Fas蛋白阳性组中 ,浸润淋巴细胞FasL染色程度与癌细胞凋亡指数呈正相关 (P <0 0 1) ,FasL染色越强 ,凋亡癌细胞越多。Fas蛋白阴性组中则不存在这种相关性。　结论　癌旁浸润淋巴细胞通过其表面的FasL与大肠癌细胞表面的Fas蛋白作用 ,是诱导癌细胞凋亡的途经之一。提高癌细胞Fas蛋白的表达及应用特异性Fas抗体 ,将为大肠癌治疗提供新思路。

Expression of Fas ligand on peritumoral lymphocytes and its association with apoptosis of colorectal carcinomas

OBJECTIVE: To study the expression of Fas ligand on peritumoral lymphocytes and its relation to the apoptosis of colorectal carcinoma. METHODS: The expression of Fas protein and FasL in 86 cases of colorectal carcinomas and normal colorectal tissues at the margins of resection was studied immunohistochemically. Apoptosis of cancer cells was evaluated with TUNEL method, which was then correlated with FasL expression on peritumoral lymphocytes. RESULTS: 53 (61.6%) of 86 cases of colorectal carcinoma were stained positively with Fas monoclonal antibodies, but such stain was net found in the normal colorectal tissues at the margin of resection. Peritumoral lymphocytes of 69 cases (80.2%) were stained positively with FasL antibodies. The intensity of FasL staining on peritumoral lymphocytes was positively correlated with the apoptotic index of cancer cells in the Fas positive colorectal carcinomas (P < 0.01), but not in the Fas negative group. CONCLUSION: FasL expressed on the surfaces of peritumoral lymphocytes mediates apoptosis of colorectal cancer cells by acting on its receptor, Fas protein on cancer cells. The elevation of Fas expression on cancer cells and application of specific Fas antibodies may serve as new approaches to treat colorectal carcinoma.