胃癌患者肿瘤组织与外周血T细胞受体CDR3的差异分析

The variation analysis of T-cell receptor repertoire in tumor tissue and blood from gastric cancer patients

目的:采用高通量测序技术研究胃癌患者肿瘤组织、癌旁组织及血液中T细胞表面抗原受体(TCR)的构成及克隆表达等特性。方法:收集7例胃癌病例的肿瘤组织、癌旁组织、外周血标本,提取DNA,经多重PCR,对TCRβ链CDR3区进行建库,采用Illumina HiSeq 2000测序系统测序,经过数据处理和比对分析,比较胃癌组织TCR CDR3组库的组成特征。结果:通过比较胃癌的三组标本的TCRβ链CDR3区克隆表达情况,获得了23种差异取用的VJ基因组合及41种差异取用的氨基酸序列,但三组样品间TCR CDR3克隆型的分布无显著差异。结论:胃癌患者癌旁组织、肿瘤组织及外周血存在差异取用的VJ基因组合及氨基酸序列。尽管不同组织中CDR3克隆型的分布并无显著差异,癌旁组织可能受到肿瘤组织及循环血液的共同影响,克隆型多数为低表达,多样性更高。进一步研究癌旁组织的TCR克隆型特征对于明确胃癌肿瘤微环境的特性及肿瘤特异性抗原的鉴定可能具有重要意义。

Objective:To study the characteristics of the T-cell receptor repertoires in the cancer tissues,the paired adjacent normal tissues,and the peripheral blood of gastric cancer patients using high-throughput sequencing(HTS).Methods:The cancer tissues,the paired adjacent normal tissues,and peripheral blood were collected from 7 gastric cancer patients.After DNA extractions,multiplex PCRs were performed to amplify the CDR3 region of TCRB.The high-throughput sequencings were carried out using Illumina HiSeq 2000 system.The sequencing data was analyzed to study the compositions and variations of CDR3 in different tissues.Results:Twenty three kinds of TCRB V-J usages and 41 CDR3 AA sequences were identified with significantly different frequencies in the 3 groups of samples.But no significant differences were observed in the total CDR3 clonotypes,unique clonotypes or hyper express clonotypes in the 3 groups of samples.Conclusion:There were different V-J usages and AA sequences in the cancer tissues,the paired adjacent normal tissues,and the peripheral blood of gastric cancer patients.Although no significant differences were identified in the clonetype distributions,the paired adjacent normal tissues were influenced by both peripheral blood and cancer tissues,the details of CDR3 clonotypes in adjacent normal tissues may be critical for better understanding of the tumor microenvironment and the identification of tumor specific antigens in gastric cancer.