β_2-微球蛋白mRNA低表达在肝细胞癌免疫逃逸中的作用

Down-Regulation of the mRNA Level of β_2-Microgloblin in Hepatocellular Carcinoma and its Effect in Tumor Escape from Immune Recognition

目的:研究肝细胞癌(HCC)组织中人白细胞抗原(HLA)Ⅰ类分子轻链β2-微球蛋白(β2-m)在肿瘤免疫逃逸中的作用,探讨肝硬化背景对肝癌组织内β2-m的mRNA水平的影响。方法:RT-PCR法检测40例肝癌和癌旁组织中β2-m的mRNA水平,并从不同角度进行分析。结果:肝癌组织中β2-m基因mRNA水平显著低于非癌组织,肝硬变背景下肝癌组织内β2-m的mRNA水平低于无肝硬化背景的肝癌组织。结论:肝癌组织中β2-m基因mRNA水平下调,可致肝癌细胞表面HLA-Ⅰ类分子低表达,这一变化与肿瘤细胞的免疫逃逸相关;HCC病人的肝硬变背景在这一机制中可能起到了某种程度的促进作用。

Objective： To analyze the mRNA level of β2-microgloblin（β2-m） in hepatocellular carcinoma（HCC） to serve as an evidence that tumor cells can reduce their immunogenicity to evade the attack from immunocytes as a result of their lower expression of class I HLA molecule. To investigate if liver cirrhosis can affect the mRNA lever of β2-m in HCC. Methods： The mRNA was extracted from liver cancer and its paracancerous tissue from fourty patients and semiquantitatively analyzed by RT-PCR technique. Results： The mRNA of β2-m in HCC was significantly lower than that of patched paracancerous tissue and showed less level in tissue with liver cirrhosis than without. Conclusion： Down-regulated β2-m gene led to unstability and incapacity of HLA complex and then made tumor cells escape from body immunal surveillance. The patients＇ cirrhosis backgrounds have somewhat played as a promoter in tumor escape mechanism.