ABCG2在肺癌中的表达及意义

目的 ATP结合转运蛋白G超家族成员2(ABCG2)属膜转运体ABC超家族,参与肿瘤的耐药.本研究旨在探讨ABCG2在肺癌中的表达及意义.方法 选用83例(64例非小细胞肺癌和19例小细胞肺癌)肺癌患者手术及活检标本.这些患者在取组织标本前均未行化疗或放疗.采用免疫组化法检测83例肺癌组织中ABCG2的表达.分别设阳性和阴性对照.另外取5例正常肺组织作比较研究.结果 ABCG2阳性染色定位于癌细胞胞膜,部分病例胞浆也有分布.83例肺癌中,免疫组化显示非小细胞肺癌ABCG2阳性率71.88%(46/64),明显高于小细胞肺癌10.53%(2/19,P＜0.05).在非小细胞癌中ABCG2的表达与患者性别,肿瘤大小及病理类型无相关性(P＞0.05),但ABCG2在无淋巴结转移和有淋巴结转移的非小细胞癌中表达有显著性差异(P＜0.05).同时ABCG2表达与非小细胞癌分化程度也具有相关性(P＜0.05).而用于比较研究的5例正常肺组织未观察到ABCG2阳性染色.结论 ABCG2在非小细胞肺癌的发生、发展过程中可能起着重要作用,它有可能成为治疗非小细胞肺癌临床耐药的分子靶标.

Expression and significance of ABCG2 in lung cancer

Objective ABCG2(ATP-binding cassette superfamily G member 2)is a member of ABC transporter superfamily,and participates in the mechanisms of high resistance to chemotherapeutic agents in tumor treatment.The aim of present study is to investigate the expression and significance of ABCG2 in lung cancer tissues.Methods Lung cancer tissues were obtained from 83 patients(64 NSCLC,19 SCLC)by bio-autopsy or surgery.No patients had received chemotherapy or radiotherapy before bio-autopsy or surgery.83 lung cancer specimens were analyzed for ABCG2 protein expression by using immunohistochemistry.Negative controls had the primary antibody eliminated.Human placenta tissues were used as positive control.In addition,five specimens of normal lung tissues were included for comparative study.Results The present study confirmed the predominant localization of ABCG2 transporter in plasma membrane.Some of ABCG2-positive tumors showed mixed membranous and cytoplasmic staining.ABCG2 expression was found in 71.9%(46/64)of NSCLC and 10.5%(2/19)of SCLC.The level of ABCG2 expression was significantly higher in NSCLC than in SCLC(P<0.05).Moreover,the level of ABCG2 expression was not related with gender,histology,tumor size and stage in NSCLC.There were significant correlations between the expression of ABCG2 and the clinical variables including lymph node metastasis and differentiation in NSCLC.Five specimens of normal lung tissues for comparative study showed no any ABCG2 immunoreactivity.Conclusion The expression of ABCG2 found in NSCLC tissues may be closely related to oncogenesis and progress of NSCLC.The ABCG2 may serve as a molecular target for reducing drug resistance to chemotherapy in NSCLC.