肝细胞癌nm23H1基因遗传不稳定性与临床病理特征的相关性研究

目的： 研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失，对肝细胞癌nm23H1蛋白表达的影响，阐明nm23H1基因遗传不稳定性与肝细胞癌及临床病理特征的关系，为揭示nm23H1基因作用机制和肿瘤发生、转移机理提供实验依据。方法： 采用石蜡包埋组织抽提DNA，PCR-单链构象多态性（PCR-SSCP），常规银染，Envision免疫组织化学和Leica-Qwin计算机图像分析等方法进行nm23H1基因遗传不稳定性研究。 结果： ① 48例肝细胞癌D17S396位点遗传不稳定性的发生率为35.42%。LOH的发生率在有无淋巴结或远处转移和有无肝内转移或门静脉栓的癌组织中有显著差异（P<0.01），临床TNM分期Ⅲ期LOH的发生率显著高于Ⅰ、Ⅱ期（P<0.01）。此外，在侵袭转移高危组LOH的发生率显著高于侵袭转移低危组 (P<0.01)。MSI检出率与肝细胞癌临床病理参数均无关。② nm23H1蛋白阳性率为56.25%，nm23H1蛋白阳性率在Edmondson分级Ⅲ +Ⅳ组低于Ⅰ+ Ⅱ组（P<0.01） ，在有淋巴或远处转移组显著低于无淋巴或远处转移组（P<0.01）,TNM分期Ⅲ期显著低于Ⅰ+Ⅱ期（P<0.01）；在侵袭转移高危组中nm23H1蛋白阳性率显著低于侵袭转移低危组 (P<0.01)。此外，计算机图像定量分析显示，在各临床病理参数影响下，nm23H1蛋白的表达强度没有差异。③ LOH阳性组中nm23H1蛋白阳性率为27.27％，显著低于LOH阴性组64.86％，两者差异显著（P<0.05）。结论： nm23H1基因的MSI和LOH通过相互独立的途径调控肝细胞癌的发生和转移，后者可抑制肝细胞癌局部nm23H1蛋白的表达，并赋予肝细胞癌高转移、预后差的特性。提高肝细胞癌局部nm23H1蛋白的表达，可减缓肿瘤的侵袭转移倾向，并改善预后。

Relationship between genetic instability of nm23H1 gene and clinical pathological characteristic in hepatocellular carcinoma

AIM: The aim of this study was to examine the microstatellite instability (MSI) and loss of heterozygosity(LOH) of locus D17S396 on chromosome 17 and their influence on the expression of nm23H1 in hepatocellular carcinoma (HCC),which may provide experimental evidence for the mechanism of nm23H1 gene and tumor metastasis.METHODS: Techniques such as DNA extraction from formalin-fixed paraffin-embedded tissues,PCR-SSCP,ordinary silver stain were used to study MSI and LOH of locus D17S396.Envision immunohistochemistry and Leica-Qwin computer imaging techniques were used to assess the expression of nm23H1.RESULTS: ① The frequency of heredity instability of HCCs was 35.42%.The frequency of LOH in the cases with lymph node or distant organs metastasis or not and with intrahepatic metastasis or embolus of portal vein or not was significantly different (P<0.01),it was higher in stage TNM Ⅲ than that in stageⅠ and Ⅱ.Moreover,it was higher in high tendency to invasion or metastasis cases than that in the low tendency cases (P<0.01).② The expression of nm23H1 was 56.25%.It was significantly different in Edmondson grade,TNM stage and in lymph node or distant organ metastasis cases (P<0.01).The cases with high tendency of invasion or metastasis exhibited lower nm23H1 expression compared with low tendency cases (P<0.01).③ The positive rate of nm23H1 protein in LOH positive group was lower than that in LOH negative group (P<0.05).CONCLUSION: The results indicate that both MSI and LOH of nm23H1 gene control the development of HCC independently in different pathways.LOH inhibits the expression of nm23H1,which endows it with high aggressive and poor prognosis.Increase in the amount of nm23H1 protein expression effectively restrains the tendency to invasion or metastasis of HCCs and improves prognosis of patients.