非小细胞肺癌细胞学标本检测表皮生长因子受体和K—ras基因的突变

Detection of EGFR and K-ras mutations in non-small cell lung cancer using cytological specimens

目的 探讨采用非小细胞肺癌（NSCLC）相关细胞学标本检测表皮生长因子受体（EGFR）和K—ras基因突变的可行性。方法收集50例NSCLC患者的纤维支气管镜（FOB）、细针穿刺（FNA）和胸水（PLE）细胞学标本，采用PCR技术扩增EGFR基因第18～21外显子和K—ras基因第12、13号密码子，并对扩增片段进行测序和分析。结果50例NSCLC细胞学标本的DNA提取满意率为86．0％（43／50），其中42例有特异性PCR扩增产物可以进行测序。42例标本中，EGFR基因的突变率为33．3％（14／42），其中EGFR基因第19外显子的突变率为16．7％（7／42），第20外显子的突变率为4．8％（2／42），第21外显子的突变率为11．9％（5／42），未检出第18外显子突变。EGFR基因第19和21外显子突变占EGFR突变的85．7％（12／14）。经组织病理学证实为肺腺癌患者的EGFR突变率为38．7％（12／31）。42例NSCLC患者细胞学标本中，K—ras基因的突变率为4．8％（2／42），未发现EGFR基因突变与K—ras基因突变存在于同一病例。结论采用NSCLC细胞学标本进行EGFR和K—r／is基因突变检测，方法可行，结果可靠，对无法获得组织学标本的肺癌患者可以尝试采用细胞学标本进行检测。

Objective To validate the feasibility for detecting EGFR and k-ras mutations using cytological specimens. Methods Cytological specimens including fine-needle aspiration （FNA）, pleural effusion （PLE） and fiberoptic bronchoscopic （FOB） brushing were collected from patients with non-small cell lung cancer （ NSCLC ） from January 2011 to July 2011 at the Department of Cytology, Cancer Hospital, Chinese Academy of Medical Sciences （CHCAMS）. Polymerase chain reaction （PCR） was carried out to amplify EGFR exons 18-21 and k-ras codons 12-13, and then the PCR products sequencing and analysis were performed. Results Fifty cytological specimens were collected including 19 cases of FOB, 9 cases of FNA, 22 cases of PLE. Of them DNA was successfully extracted in 43 cases, and specific PCR amplification products sequencing were performed in 42 cases. EGFR mutations were detected in 14 of 42 specimens （ 33.3% ）, the frequencies of EGFR mutations in exons 19, 20 and21 were 16.7% （7/42）, 4.8% （2/42） and 11.9% （5/42）, respectively, and no mutation was found in exon 18. Higher frequencies of EGFR mutations were detected in exons 19 and 21 （ 85.7% ）. Mutations were identified in 38.7% （ 12/31 ） cases of adenoeareinoma. K-ras mutations were found in 2 of 42 specimens （4.8%）. EGFR and K-ras mutations were not found in the same case. Conclusions Cytological specimens are feasible for detecting EGFR and K-ras mutation. This is especially beneficial in patients in whom histological materials can not be obtained.