非小细胞肺癌患者外周血及组织中p53基因突变的研究

p53 Gene Mutation in Plasma and Tumor of Patients with Non-Small Cell Lung Cancer

目的探讨非小细胞肺癌(NSCLC)患者外周血中p53基因突变检测的可行性及其临床意义。方法应用PCR-SSCP分析技术,检测69例原发性NSCLC患者血浆(手术前、后)及对应新鲜肺肿瘤组织中p53基因5～8外显子的突变情况,以15例肺良性病变组织及血浆、5例健康献血员血浆作对照。并同时对相应的组织病理切片进行p53蛋白的免疫组化染色检测。结果NSCLC患者血浆(术前)和对应肿瘤组织中p53基因突变率分别为38%(26/69例)、54%(37/69例),其共同检出率达54%(20/37例);而对照组肺良性病变及健康人血浆中均未检出该基因突变。术后血浆中p53突变率明显低于术前,仅7例(10%)检测到p53突变,包括Ⅲ期3例,Ⅳ期4例,多为有远处转移的患者。免疫组化染色p53蛋白表达阳性率为64%(44/69例),PCR-SSCP分析与免疫组化染色两种方法检测符合率为81%(56/69例)。NSCLC患者血浆(术前)中p53基因突变在不同临床分期及有无淋巴结转移间差异有统计学意义(P<0.05)。肿瘤组织中该基因的突变及表达在有无淋巴结转移患者间差异有统计学意义(P<0.05),而在不同病理分型、分化程度及临床分期间差异均无统计学意义(均P>0.05)。结论p53基因突变在NSCLC患者血浆与原发肿瘤组织中有较高的一致性和检出率,且其改变与NSCLC临床分期和转移相关;监测肺癌患者手术前、后血浆中p53突变具有一定意义,通过检测外周血中p53基因的改变可能对肺癌的诊断、预后判断及术后追踪具有一定价值。

Objective To study the clinical value of detecting p53 gene mutations in plasma of non-small cell lung cancer patients. Methods Polymerase chain reaction single-strand conformation polymorphism （PCR-SSCP） assay was performed to examine the point mutations in the conserved exons 5, 6, 7 and 8 of p53 in plasma （pre- and post- operation） and matched primary tumor tissues of 69 patients with non-small cell lung cancer. Immunohistochemistry （LSAB） was also used to detect p53 protein accumulation in the tissues. Fifteen patients with benign lung diseases and 5 healthy volunteers were taken as control group. Results The frequency of p53 gene mutations in plasma （pre-operation） and primary lung cancer tissues was 38% （26/ 69） and 54% （37/69）, respectively. Their common positive rate was 54% （20/37）. Neither the plasma from benign lung diseases and tissues nor control plasma from healthy volunteers showed p53 gene mutation. It was just 7 cases （10%） who had the mutation of p53 gene in plasma from patients with postoperative lung cancer, that was significantly lower than that before operation, and most of them occurred in patients with distant metastasis. The general positive rate for immunohistochemistry was 64% in 69 cases of lung cancer, and the concordance rate of immunohistochemistry and PCR-SSCP was 81% （56/69）. The extent of p53 gene mutations in plasma （pre-operation） was associated with stages of TNM classification and lymph node metastasis, and the difference was statistically significant （P〈0.05）. The occurrence of p53 mutations and its over-expression in lung caner tissues were related to lymph node metastasis （P〈0.05）, but not to histological grade, subtype and TNM stage （P〉 0.05）. Conclusion p53 gene mutations show a high concordant pattern between plasma and matched tissues of non-small cell lung cancer patients, and its changes are related to TNM stage and lymph node metastasis. Monitoring of sequential changes of pre- and post-operative plasma p53 mutations in patients with lung cancer could have some potential significance, which may be helpful to the diagnosis and prognosis of lung cancer.