肺癌组织中黑色素瘤抗原-A3基因mRNA的表达及其序列点突变分析

目的检测肺癌组织中黑色素瘤抗原-3基因(MAGE-A3)mRNA的表达。方法用逆转录-套式聚合酶链反应(RT-PCR)对31例肺癌患者癌组织和相应癌旁组织MAGE-A3mRNA表达情况进行测定;PE-377DNA测序仪对5例10个RT-PCR扩增产物中的目的基因片段进行DNA序列测定。结果31例肺癌患者癌组织中26例表达MAGE-A3mRNA,阳性率为83.9%;相应的癌旁组织均未表达。DNA序列测定证明PCR扩增产物中目的基因片段均为MAGE-A3cDNA序列,所测5例样本中4例样本有两个相同位置的碱基发生了点突变(C2773→T2773;G2807→A2807),导致一个氨基酸残基改变(E143→K)。结论MAGE-A3mRNA在肺癌中呈高比例表达,提示此抗原有可能作为肺癌患者免疫治疗的靶抗原。我国肺癌患者中存在MAGE-A3基因个别位点的变异。

Expression and Mutation of MAGE-A3 mRNA in Lung Cancer Tissues

Objective: To investigate the expression of MAGE-A3 mRNA in tissue samples derived fromlung cancers and to discuss the possibility of using MAGE-A3 antigens as a new peptide vaccine forimmunotherapy for lung cancers. Methods: Tumor tissue samples of lung cancers and paired non-tumortissues of the lung were obtained from 31 lung cancer patients. Total RNA was extracted and cDNA wassynthesized. Nested polymerase chain reaction amplification using MAGE-A3 specific primer was performedto detect the expression of MAGE-A3. The 10 clones of 5 samples of MAGE-A3 mRNA positive PCRproducts were DNA sequenced by using DNAs sequencer (PE-377). Results: Of 31 lung cancers, 26 (83.9%)expressed MAGE-A3 mRNA. The expression of MAGE-A3 gene was not detectable in the adjacent lungtissues. The DNA sequencing confirmed that the target gene fragment in all 5 samples of PCR products wasMAGE-A3 cDNA. Point mutations occurred in 4 samples (8 clones) detected (C2773A2807) resulting in alternation of amino acid residue in one position (E143MAGE-A3 gene was expressed exclusively in tumor tissues of the patients with lung cancer in China. Thistumor rejection antigen may have potential to be used as a new peptide vaccine for immunotherapy forlung cancers. (2) There are two point mutations of MAGE-A3 gene sequence in some Chinese lung cancerpatients.