中文摘要：

目的：探讨DNA错配修复基因（MMR）蛋白表达缺失在筛选遗传性非息肉病性大肠癌（HNPCC）中的作用及其意义、方法：对收集的166倒石蜡包埋的疑似遗传性非息肉病性大肠癌组织进行MMR蛋白免疫组化染色，结果：hMLHl蛋白表达阴性（0分）25例，占15．53％，阳性（1～4分）136例，占84‘47％；在右半结肠、左半结肠和直肠表达缺失率分别为26．67％（12／45）、5．13％（2／39）和14．29％（11／77）；右半结肠癌11MLHl蛋白的表达缺失明显高于左半结肠癌（P〈0．05），但与直肠癌无显著性差别（P〉0．05）。hMSH2蛋白表达阴性（0分）35倒，占21．08％，阳性（1～4分）126例，占75．9％；在右半、左半结肠和直肠表达缺失率分别为33_33％（15／45）、15138％（6／39）和18．18％（14／77）；右半结肠癌的表达缺失明显高于左半结肠癌（P〈0．05）和直肠癌（P〈0．01），结论：MMR蛋白免疫组化染色作为一个简单易行的方法在今后检测和确定遗传性非息内病性大肠癌中将发挥重要作用，

英文摘要：

To evaluate the significance of the lack of expression of mismatch repair genes （MMR） in screening for hereditary nonpolyposis eolorectal eaneer（HNPCC）. Methods： One hun-dred sixty-six patients with suspected HNPCC that were younger than 40 years of age were assessed for DNA mismatch repair deficiency by immunohistochemical detection of the hMLH1 and hMSH2 gene products. Results： Of the 166 patients, 25 （15.53%） showed no detectable expression of hMI, HI, 136 （84.47%） showed normal expression of hMLH1, 35（21.08%） showed no detectable expression of hMSH2, and 126 （75.9%） showed normal expression of hMSH2. Loss of expression of at leasl one of lhese MMR proteins was found in 80 of the 166 （48.19%）. The rate of negative hMLHI protein expression in tumors in the right colon, left colon and rectum was 26.67%（12/45）, 5.13% （2/39）, and 14.29%（11/77）, respectively, and the rate of negative hMSH2 protein expression in tumors in the right colon, left colon and reetum was 33.33%（15/45）, 15.38%（6/39） and 18.18%（4/77）, respectively. Conclusion： Our results suggest that defects in the DNA mismatch repair system are frequent in young Chinese patients with colorectal cancer. Imunohistoehemical detection is useful for identifying HNPCC among young patients with colorectal cancer.