中国人肝癌分泌型卷曲相关蛋白1基因遗传的不稳定性

Genetic instability of the sFRP1 gene in hepatocellular carcinoma in Chinese people

目的研究8号染色体上D8S532位点的杂合性缺失（LOH）和微卫星不稳定性（MSI）对分泌型卷曲相关蛋白1基因（sFRP1）蛋白表达的影响,阐明sFRP1基因遗传不稳定性与肝癌进展的关系,为揭示sFRP1基因作用机制和肿瘤发生发展机制提供实验依据。方法采用石蜡包埋组织抽提DNA,聚合酶链-单链构象多态性（PCR-SSCP）分析,常规银染检测D8S532位点的LOH和MSI,采用Envision免疫组织化学染色,Leica-Qwin计算机图像分析系统采图和Image-Pro P1uS（IPP）Version5.0专业图像分析软件分析蛋白表达。结果在36例肝癌中,D8S532位点LOH和MSI检出率分别为11.11%（4/36）和8.33%（3/36）,D8S532位点MSI发生率在60岁以上年龄组（≥60）26.67%（4/15）,高于60岁以下年龄组（＆lt;60）0.00%（0/21,P＆lt;0.05）。相比较于正常组织,86.11%（31/36）的sFRP1蛋白有不同程度表达下降,在肝癌组织中,sFRP1表达阳性率为52.78%（19/36）,蛋白表达阴性组LOH阳性率为23.53%（4/17）,明显高于蛋白阳性组...

Objective To examine loss of heterozygosity （LOH） and microsatellite instability （MSI） of locus D8S532 on chromosome 8 and their influence on the expression of sFRP1 in the hepatocellular carcinoma （HCCs）, which may provide an experimental evidence for clarifying the mechanism of sFRPI gene and tumor development. Methods DNA was extracted from formalin-fixed paraffin-embedded tissues. Polymerase chain reaction-single strand conformation polymorphism （PCR-SSCP） and ordinary silver stain were used to study LOH and MSI of locus D8S532. Envision immunohistochemistry, Leiea-Qwin computerized imaging system and Image-Pro Plus （IPP） version 4.5 professional imaging analysis software were used to assess the expression of sFRP1. Results The detection rates of LOH and MSI of locus D8S532 in the 36 specimens of HCC were 11.11% and 8.33 % respectively. The down-regulation of sFRP1 was observed in 31 of 36 HCCs （86.11% ） compared with non-carcinoma liver tissues, and the positive rate of sFRP1 protein of the HCCs was 52.78% （ 19/36 ）. The frequency of LOH was lower in the cases with positive expression of sFRP1 protein than those negative （0 vs 23.53 %, P 〈 0.05 ）. Conclusion It was a common phenomenon that expression of sFRP1 protein is negative or low in Chinese with HCCs. The genetic instability of sFRP1 gene was one of causes, which lead to HCCs. LOH may play a major role in negative expression of sFRP1.