抑癌基因p16和RB与肺癌早期诊断的临床实验研究

目的 研究肺癌组织中ｐ１６和ＲＢ基因失活的比率和失活的机制,探讨其与肺癌生物学特性及临床、病理和基因分型诊断的关系。方法 采用免疫组化、双重原位杂交、ＰＣＲ、ＰＣＲ－ＳＳＣＰ以及序列分析等方法,检测１０６例肺癌患者的癌组织和正常肺组织以及２３例肺良性疾病标本抑癌基因ｐ１６和ＲＢ的改变,并做对比研究。结果 肺癌细胞ｐ１６ＲＢ在蛋白和ｍＲＮＡ水平的表达明显低于正常肺组织和良性疾病肺组织,且与肺癌组织学类型、有无淋巴结转移以及临床病理分期密切相关,较早期肺癌（Ⅰ、Ⅱ期）病例即 较显著的抑癌基因０ｐ１６和ＲＢ的失活（３２．６％和２８．３％）;非小细胞肺 以ｐ１６基因失活为主（５０．１％）,小细胞肺癌以ＲＢ基因失活为主（８８．２％）,ｐ１６基因失活的主要机制有纯合缺失、甲基化和点突变。结论 抑癌基因ｐ１６和ＲＢ在肺癌发生

Relations of tumor suppressor gene p16 and RB to early diagnosis of lung cancer

OBJECTIVES: To study the incidence and mechanism of the tumor suppressor gene p16 and RB inactivation in lung cancer, and to investigate their relations to biological characteristics, clinical pathological diagnosis and gene classification. METHODS: Immunohistochemistry, double in situ hybridization, PCR, PCR-SSCP, and sequencing were used to study the changes in the p16 and RB genes in 106 patients with lung cancer. The specimen of normal lung tissue from the patients with lung cancer and specimens of the 23 patients with benign lung diseases were studied in contrast to those of the same patients. RESULTS: The total expression rate of the p16 and RB genes in the lung cancer tissues of the 106 patients was lower than that in normal lung tissues and tissues of benign lung diseases and was specially related to histological type, metastasis, and clinical stage of lung cancer. In stage I and II lung cancer, the obvious inactivation rate of the tumor suppressor gene p16 or RB was 32.6% or 28.3%. The p16 inactivation appeared largely in non-small cell lung cancer (50.1%), and the RB inactivation largely in small cell lung cancer (88.2%). Homozygous deletion, methylation, and mutation were three mechanisms for the p16 gene inactivation. The deletion rate of the p16 exon 1 and/or exon 2 was 25.8% in the patients with non-small cell lung cancer. Fifteen patients (16.9%) showed methylation at the SmaI sites of CpG island of the p16 gene. PCR-SSCP and sequencing revealed p16 gene mutation in 9 of the 106 patients with lung cancer. CONCLUSIONS: The p16 and RB genes may play an important role in genesis and progression of lung cancer. The inactivation of the p16 or RB gene may be an early sign of lung canceration, that is important for the early diagnosis. A new gene classification model for lung cancer diagnosis would be set up based on the research of the p16 and RB genes.