炭末沉着症和p16~(ink4a)基因异常甲基化对小型肺腺癌发生进展的影响

背景与目的 炭末沉着症系长期吸入非生产性粉尘而导致各级支气管壁粘膜和肺膜内有炭末斑形成,可致支气管变形及破坏.有研究表明,炭末沉着症与小型肺腺癌的发生和进展密切相关.本研究旨在探讨炭末沉着症与p16ink4a基因异常甲基化修饰程度在小型肺腺癌发生和进展过程中的影响.方法应用Methylation Specific PCR技术检测68例原发性小型肺腺痛患者的癌组织、癌周正常组织中的p16ink4a基因启动子区域的异常甲基化修饰程度;炭末定量分析法来检测患者肺内的炭末沉着量;采用野口氏病理分型.结果 重度吸烟者(吸烟指数>600)的平均炭末沉着量明显高于轻度吸烟者(吸烟指数<600)和非吸烟者(P=0.005);重度吸烟者的p16ink4a基因异常甲基化检出率为60%,也明显高于轻度吸烟者和非吸烟者的27%(P=0.023);早期小型肺腺癌的p16ink4a基因异常甲基化检出率低于进展期和低分化小型腺癌,但无统计学意义;p16ink4a基因调控产物表达早期小型腺癌高于低分化小型腺癌(P=0.032).结论 炭末沉着定量分析与p16ink4a基因异常甲基化检测二者结合,有可能应用于对吸烟人群的肺腺癌早期发现和早期诊断.

The influence of anthracosis and p16ink4a gene abberant methylation to the oncogenesis and progression of small pulmonary adenocarcinoma

Background and objective Anthracosis is black dust matter deposition in the pulmonary parenchyma, which can cause bronchial deformity and destruction. Previously reported, anthracosis is closely correlated to the oncogenesis and progression of small pulmonary adenocarcinoma and p16ink4a gene aberrant methylation was closely associated with lung carcinogenesis. In this study, we want to characterize the influence of anthracosis and p16ink4a gene aberrant methylation on small adenocarcinoma. Methods DNA was bisulfite modified and then Methylation Specific PCR was used to detect p16ink4a gene aberrant methylation, and black dust matter was extracted from lung tissues, the absolute absorbance (A) detected by densitometry was defined as anthracotic index (AI). The histopathologic diagnosis was according to Noguchi's classification for small pulmonary adenocarcinoma. Results For heavy smokers, the mean AI was significantly higher than that of nonsmokers (P=0.005) and the frequency of p16ink4a gene aberrant methylation was also significantly higher than that of nonsmokers (P=0.023). The frequency of p16ink4a gene aberrant methylation of early stage small adenocarcinoma was lower than that of advanced and poor differentiated small adenocarcinoma, otherwise p16ink4a protein expression of early stage small adenocarcinoma was significantly higher than that of poor differentiated small adenocarcinoma (P=0.032). Conclusion AI and p16ink4a gene aberrant methylation detection could be used as a combined potential biomarker of small adenocarcinoma.