CDK4基因突变及其胰蛋白酶-抗胰蛋白酶失衡在胃癌发生中的作用

目的探讨胃癌患者中细胞周期蛋白依赖激酶基因(cell cycle-dependent protein kinase 4,CDK4)突变及其胃癌组织CDK4表达和血清胰蛋白酶-抗胰蛋白酶的失衡情况。方法应用PCR法扩增25例胃癌患者及62名健康体检者的CDK4基因外显子、启动子和侧翼序列,产物纯化后直接测序,分析不同基因型胃癌患者的临床特征,取患者的癌组织、癌旁组织和远离癌的正常组织做CDK4免疫组化,同时应用ELISA法检测同一时期患者及其对照的血清胰蛋白酶和α-抗胰蛋白酶水平,分析其差异性。结果在胃癌患者中发现CDK4基因3号外显子存在高频突变,其中5例患者为c.110 TA突变,突变造成p.M37T;免疫组化显示,癌组织高表达CDK4,癌旁组织呈弱表达,远离癌的正常组织呈阴性;胃癌患者的血清胰蛋白酶浓度(33.98±11.24)ng/ml显著高于正常对照组(15.96±18.23)ng/ml,而血清抗胰蛋白酶浓度与正常对照组相比,差异无统计学意义(P0.05)。结论 CDK4基因突变及其高表达与胃癌发生密切相关,机体内胰蛋白酶-抗胰蛋白酶的失衡可能是胃癌发病的重要原因。

Role of mutation of CDK4 gene and imbalance of serum trypsin-antitrypsin in gastric carcinoma

Objective To investigate the mutation and expression of cell cycle-dependent protein kinase 4 （CDK4） in gastric carcinoma, and investigate the imbalance of serum trypsin and antitrypsin in gastric carcinoma. Methods In the 25 cases gastric carcinoma and 62 cases healthy controls, PCR was performed to amplify the CDK4, including exon, promoter and flanking sequence. The gene was sequenced after purification. The clinical characteristics were analyzed a- mong different genotypes. Immunohistochemistry of CDK4 was performed on carcinoma tissue, para-carcinoma tissue and normal tissue. Meanwhile, the serum trypsin and antitrypsin in the gastric carcinoma and healthy controls were detected by ELISA. Results High frequency of exon 3 mutation was found in gastric carcinoma. Five patients carried e. 110 T 〉 A, which leaded to p. M37T. The expression of CDK4 in carcinoma tissue, para-carcinoma tissue and normal tissue were high, weak and negative, respectively. The concentration of serum trypsin in gastric carcinoma was significantly higher than that in healthy controls （33.98 ± 11.24） ng/ml vs （ 15.96 ± 18.23 ） ng/ml] , however, there was no sig- nificant difference about the concentration of serum antitrypsin between two groups （P 〉 0.05）. Conclusion Mutation and high expression of CDK4 is closely related to gastric carcinoma. The imbalance of serum trypsin and antitrypsin may play an important role in mechanism of gastric carcinoma.