摘要
AIM： To detect germline mutations of MLH1, and investigate microsatellite instability and expression of MLH1 in tumor tissues of hereditary non-polyposis colorectal cancer （HNPCC） with two novel germline mutations, and further investigate the pathobiology of the two novel mutations of MLH1. METHODS： RNA was extracted from the peripheral blood of 12 patients from 12 different families that fulfilled the Amsterdam 11 Criteria for HNPCC. Germline mutations of MLH1 were determined by RT-PCR, followed by cDNA sequencing analysis. PCR-GeneScan analysis was used to investigate microsatellite instability with a panel of five microsatellite markers （BAT26, BAT25, D5S346, D2S123 and mfd15）, along with immunohistochemical staining to detect the expression of MLH1 protein in two patients＇ tumor tissues with novel mutations. RESULTS： Three germline mutations were found in four patients, one of the mutations has previously been reported, but the other two, CGC→TGC at codon 217 of exon 8 and CCG→CTG at codon 581 of exon 16, have not been reported. The two patients＇ tumor tissues with novel mutations had high-frequency microsatellite instability that showed more than two unstable loci, and both tumors lost their MLH1 protein expression. CONCLUSION： The two novel germline mutations of MLH1 in HNPCC families i.e. CGC→TGC at codon 217 of exon 8 and CCG→CTG at codon 581 of exon 16, are very likely to have pathological significance.
瞄准：检测 MLH1 的细菌线变化，并且在世袭 non-polyposis 颜色的肿瘤纸巾调查微卫星不稳定性和 MLH1 的表示有二个新奇细菌的表面的癌症(HNPCC ) 衬里变化，并且进一步调查 MLH1 的二个新奇变化的病理学。方法：RNA 从为 HNPCC 完成了阿姆斯特丹 II 标准的 12 个不同家庭从 12 个病人的外部血被提取。MLH1 的 Germline 变化被 RT-PCR 决定，由定序分析的 cDNA 列在后面。PCR-GeneScan 分析被用来与新奇变化在二个病人的肿瘤纸巾检测 MLH1 蛋白质的表示的组织化学的染色与五个微卫星标记(BAT26， BAT25， D5S346， D2S123 和 mfd15 ) 的一块面板调查微卫星不稳定性，与免疫一起。结果：三个细菌线变化在四个病人，被发现变化之一以前被报导了，但是其它二，在 8 上的 217 前和在 16 上的 581 前上的鳕鱼的 CCG 右箭头 CTG 上的鳕鱼的 CGC 右箭头 TGC，没被报导。二个病人有新奇变化的肿瘤纸巾有显示出超过二不稳定的部位的高周波的微卫星不稳定性，并且两个肿瘤失去了他们的 MLH1 蛋白质表示。结论：在 HNPCC 家庭的 MLH1 的二个新奇细菌线变化即在 8 上的 217 前和在 16 上的 581 前上的鳕鱼的 CCG 右箭头 CTG 上的鳕鱼的 CGC 右箭头 TGC，是很可能的有病理学的意义。
基金
the Key Project of Shanghai Medical Subjects,No.05Ⅲ004 and Shanghai Pujiang Program,No.06PJ14019
