非小细胞肺癌INK4a和ARF基因甲基化与其蛋白共表达关系的探讨

目的:分析INK4a和ARF基因启动子甲基化与其蛋白共表达之间的关系.方法:选择前期实验中p14ARF和p16INK4a蛋白共表达阴性的非小细胞肺癌(NSCLC)患者35例,共表达阳性的NSCLC患者20例作为研究对象,分别称为(p14 p16)阴性组和(p14 p16)阳性组.运用甲基化特异性PCR(MSP)方法对两组患者癌组织INK4a和ARF基因启动子的甲基化状态进行检测.结果:(p14 p16)阴性组有18例发生INK4a基因甲基化,(p14 p16)阳性组有2例发生INK4a基因甲基化,两组差异有显著意义(P＜0.01).(p14 p16)阴性组有8例发生ARF基因启动子甲基化,(p14 p16)阳性组有2例发生ARF基因启动子甲基化,两组差异无显著意义(P＞0.05).INK4a和ARF基因异常申基化相互之间无显著相关性(P＞0.05).结论:NSCLC患者肺癌组织INK4a基因甲基化是导致p16INK4a蛋白表达阴性的重要机制;INK4a和ARF基因甲基化可能是相对独立的事件.

The Relationship between INK4a/ARF Genes Methylation and Proteins Co-expression in Non-small Cell Lung Cancer

Objective: To study the relationship between INK4a/ARF genes methylation and proteins co-expression in non-small cell lung cancer. Methods: Sections were obtained from previous 10%-formalin-fixed and paraffin-embedded tissues, including 35 NSCLC samples with p14ARF and p16INK4a negative co-expression and 20 NSCLC samples with p14ARF and p16INK4a positive co-expression. These samples were divided into two groups and were named as the (p14 p16) negative group and the (p14 p16) positive group respectively. The 5'CpG islands methylation state of tumor suppressor gene INK4a/ARF was determined by methylation specific polymerase chain reaction (MSP). Results: The hypermethylation rate of INK4a gene was 51.4 %(18/35) in (p14 p16) negative group, but 10 %(2/20) in (p14 p16) positive group. There was a significant difference between the two groups (P=0.002). The hypermethylation frequency of ARF gene was 22.8 %(8/35) in the (p14 p16) negative group, and was 10 %(2/20) in the (p14 p16) positive group. There was no significant difference between the two groups(P=0.409) and was no obviously correlation between INK4a gene hypermethylation and ARF gene hypermethylation. Conclusion: INK4a gene hypermethylation is one of the important mechanisms that results in p16INK4a proteins negative expression in NSCLC. The hypermethylation of INK4a and ARF genes are independent each other.