An association between MICAgene and an increased susceptibility to oral squamous cell carcinoma

最近发现了一个新的多态基因家族，称为主要组织相容性复合体I类链相关基因A(MICA)，它位于人类白细胞抗原B基因的着丝粒附近约40kb。MICA蛋白表达在上皮细胞和多种肿瘤细胞上，起着调节免疫功能的作用。MICA蛋白被认为通过与NKG2D结合来激活粘膜组织的免疫功能，NKG2D表达在大多数自然杀伤细胞、CD8阳性T细胞和Gamma Delta T细胞上。应用聚合酶链式反应扩增和变性聚丙烯酰胺凝胶电泳法对日本口腔鳞状细胞癌患者和正常对照的MICA基因(GCT)n多态性进行了研究，发现两组患者均存在A4、A5、A6、A9和A5.1等5个等位基因。口腔鳞癌患者MICA-A5.1等位基因明显高于正常对照组，提示MICA-A5.1等位基因可能与口腔鳞癌的易感性增加有关。

Recently, a new polymorphic gene family called the major histocompatibility complex class I chain-related gene A (MICA) was discovered about 40 kb centromeric to HLA-B gene. The MICA protein, expressed on epithelial cells and many kinds of tumor cells, serves to regulate immune function. The MICA protein is thought to activate immune function on mucosal tissue by binding to NKG2D which is expressed on most natural killer cells, CD8 positive T cells, and gamma delta T cells. An association between MICA gene polymorphisms and the development of oral squamous cell carcinoma (OSCC) has also been reported.This study was designed to test this association in Japanese patients with OSCC.The (GCT)n polymorphisms of the MICA gene was investigated in OSCC patients and normal controls using polymerase chain reaction amplification and denaturing polyacrylamide gel electrophoresis.Five alleles, namely A4, A5, A6, A9, and A5.1, were found in both groups. The MICA-A5.1 allele was significantly higher in patients with OSCC when compared with normal controls These results suggest that the MICAA5.1 allele may be associated with an increased susceptibility