MHCI链相关分子A／B在胰腺癌组织中的表达及临床意义

目的：探讨MHCI链相关分子A／B（MICA／B）在胰腺癌（PDA）组织中的表达及其与胰腺癌发生发展的相关性。方法：应用免疫组化检测MICA／B在胰腺癌中的表达，分析MICA／B与胰腺癌临床病理学特征的相关性。结果：MICA／B在PDA组织中的阳性表达率为89．58％（43／48），而慢性胰腺炎和正常胰腺组织中不表达或微弱表达，癌组织与慢性胰腺炎及正常胰腺组差异显著（X2=36．069，p〈0．001）。MICA／B在胰腺癌组织中的表达水平与肿瘤的临床分期和病理分级有密切的关系（X2=8．398，10．000；P=0．015，0．003），在早期、分化较好的胰腺癌组织中MICA／B表达水平较高，而在分化较差的胰腺癌组织中表达水平较低，随着胰腺癌进展，MICA／B从肿瘤细胞表面脱落到癌细胞周围的间质组织中，晚期胰腺癌患者MICA／B的表达水平较低甚至不表达。Spearman等级相关分析显示MICA／B表达程度与分化程度正相关（r=0．331）。结论：MICA／B作为诱导蛋白通过MICA／B—NKG2D介导的免疫反应可能在早期清除胰腺癌细胞中起重要作用。但随着肿瘤的进展，MICAfB从肿瘤细胞表面脱落，释放到肿瘤间质组织进而引起肿瘤免疫逃避。因而我们推测，MICA／B-NKG2D介导的免疫监视障碍可能促进了胰腺癌的进展。

Prevalent expession of the immunostimulatory MHC class I chain-related molecules A / B in pancreatic adenocarcinoma and its clinical significance

Objective： To investigate the expression of the immunostimulatory MHC classⅠ chain-related moleculesA/B（MICA/B） in pancreatic adenocarcinoma and its clinical significance. Methods： Irnmtmohistochemistry was used to detect the expression of the immunostimulatory MHC class I chain-related molecules A / B in pancreatic carcinoma tissues samples. The relation between the expression of MICA/B and the clinical pathological factors were statistically analyzed. Results： The positive expession rate of MICA/B in 48 pancreatic carcinoma tissues samples was 89.34%（43/48）.Compared to the expression of MICA/B in normal pancreatic tissues samples and chronic pancreatitis tissues samples ,the expression of MICA/B in pancreatic carcinoma tissues samples had a statistically significant difference （x2=36.069, p 〈 0.001）. MICA/B expression rate in carcinoma tissues was related to the tumor-differentiation degree （x2=8. 398,p=0.015）and TNM staging （x2=10.000,p=0.003）. The positive rate of the MICA/B expression was increased with the increase of pathological differentiation in pancreatic cancer （p〈0.05）; The positive rate of the MICA/B expression in clinical stage of Ⅲ-Ⅳ was lower than in stage of Ⅰ -Ⅱ （p 〈0.05 ）. Spearman rank correlation displayed that the expression level of MICA/B protein was positively related to differentiation degree （r=0.331）. Conclusions： In summary, our study has suggested that the immune response induced by MICA/B-NKG2D may plays an important role in the eradiation of pancreatic carcinoma cells in the early stage, but with the tumor devel- ops,MICA/B was shed from cancer cell membrain and diffusely distributed in the stroma, so we guess that the deficiency in MI- CA/B-NKG2D immune surveillance may contribute to pancreatic cancer progression.