MICA基因多态性及血清可溶性MICA浓度与结肠癌的相关性研究

目的 观察主要组织相容性复合体Ⅰ类相关基因A(major histocompatibility complex class Ⅰ chain-related gene A,MICA)全长多态性与结肠癌的发病是否关联,以及血清可溶性主要组织相容性复合体Ⅰ类相关抗原A(major histocomptctibility complex class Ⅰ chain-related antigen A,MICA)浓度与结肠癌发病及病程的相关性.方法 应用聚合酶链反应-序列特异性引物及DNA测序分型方法,分析江苏扬州地区117例结肠癌患者和113名健康个体的MICA基因全长多态性及其编码分子第129位氨基酸残基的变化.血清可溶性MICA浓度通过酶联免疫吸附试验方法测定.结果 结肠癌患者和正常群体胞外区和跨膜区MICA等位基因的分布差异均无统计学意义,MICA跨膜区等位基因在不同病期结肠癌患者的分布差异亦无统计学意义.而结肠癌患者群体内MICA第129位氨基酸残基为蛋氨酸的频率显著降低;可溶性MICA浓度在Duke's C和D期患者血清内显著升高.结论 MICA等位基因多态性与结肠癌的发病及进展没有关联,但血清可溶性MICA浓度的检测可作为判断结肠癌预后的指标之一.

Association of MICA gene polymorphism and serum soluble MICA level with colorectal cancer

Objective To investigate whether the major histocompatibility complex class I chain-related gene A gene ( MICA) polymorphism and serum soluble MICA level were associated with the occurrence and development of colorectal cancer. Methods DNA samples from 117 colorectal cancer patients and 113 healthy individuals from Yangzhou in Jiangsu province were genotyped by using the polymerase chain reaction (PCR) and sequence-specific primer (SSP) method and PCR based sequencing. In addition, polymorphism at position 129 was also analyzed by PCR-SSP. Serum levels of soluble MICA were measured by a sandwich ELISA method. Results Neither the extracellular nor the transmembrane region polymorphisms of MICA gene were associated with the occurrence and the different stages of colorectal cancer. In contrast, the frequency of the methionine residue at position 129 was significantly decreased in the patient group. Soluble MICA levels in sera were increased in the late stages of colorectal cancer. Conclusion Although there was no genetic susceptibility attributed to MICA gene polymorphism with regard to development of colorectal cancer, serum levels of soluble MICA may be a diagnostic marker of advanced stages.