NCCN推荐流程筛选中国人遗传性非息肉病性结直肠癌的临床意义

目的探讨NCCN-2007推荐的流程筛选中国人遗传性非息肉病性结直肠癌（HNPCC）的临床意义。方法按照NCCN-2007版推荐的筛选流程，首先应用Revised Bethesda Guidelines（Revised BG）对北京大学人民医院胃肠外科2002年1月至2006年2月收治的419例临床病理资料齐全的结直肠癌患者进行HNPCC的初步筛选；然后应用免疫组织化学法进一步检测错配修复（MMR）蛋白的表达；最后通过基因测序方法来进行验证，并与原标准进行比较。EnVision二步法对90例符合Revised BG（其中符合原筛选标准——Amsterdam Ⅱ者的8例为A组，另82例为B组）患者的肿瘤组织石蜡切片进行hMLH1和hMSH2染色，初步确定患者的错配修复蛋白缺陷表型。对错配修复基因蛋白表达缺失的患者检测hMLH1和hMSH2种系突变。结果筛选出hMLH1或hMSH2蛋白表达缺失者18例（A组5例，B组13例）。临床诊断HNPCC患者最终为21例（A组8例，B组13例）。基因测序检测到B组中基因突变3例，此3例原不符合Amsterdam Ⅱ标准，但最终被确诊为HNPCC。结论NCCN推荐流程可以有效地进行HNPCC的筛选，减少临床漏诊病例。

Clinical value of screening hereditary nonpolyposis colorectal cancer in China with protocol recommended by NCCN guidelines

OBJECTIVE: To investigate the effect of the protocol recommended by NCCN-2007 on the diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC) in China. METHODS: NCCN protocol consists of identifying HNPCC characteristics according to the revised Bethesda Guidelines,genetic counseling with immunohistochemistry and finally genetic testing. Four hundred and nineteen patients diagnosed as colorectal cancer from January 2002 to February 2006 were selected. The hMLH1 and hMSH2 immunostaining were implemented for 90 patients who fulfilled the revised Bethesda Guidelines, in whom 8 patients fulfilling the Amsterdam II (Criteria were classified as group A and the other 82 patients as group B. The frozen tissues were collected from patients who showed loss of hMLH1 or hMSH2 protein expression, then RNA was extracted, and RT-PCR and cDNA sequencing were adopted to detect the germline mutations of hMLH1 and hMSH2. RESULTS: Tumor tissues from 18 patients showed loss of hMLH1 or hMSH2 protein expression (5 patients in group A and 13 in group B). Finally, 21 patients(8 in group A and 13 in group B showed loss expression of MMR protein) were diagnosed as HNPCC, including 2 cases of hMLH1 and 1 case of hMSH2 mutations. These 3 cases with cDNA mutations did not fulfill the Amsterdam II( Criteria, and were finally diagnosed as HNPCC. CONCLUSION: The protocol recommended by NCCN-2007 offers a useful approach to identify HNPCC patients,and reduces the possibility of missed diagnosis of HNPCC.