The influence of anthracosis and p16 ink4a gene aberrant methylation on small-sized pulmonary adenocarcinoma

Abstract

Aims: Anthracosis is the deposition of black dusty material in the pulmonary parenchyma. Previous reports showed anthracosis and p16(ink4a) gene aberrant methylation are closely related to the promotion and progression of small-sized pulmonary adenocarcinoma. In this study, we investigated the influence of anthracosis and p16(ink4a) gene aberrant methylation on clinical samples from patients with small-sized adenocarcinoma.

Methods and results: DNA was bisulfite modified and methylation-specific PCR was performed to detect p16(ink4a) gene aberrant methylation; black dusty material was extracted from lung tissues. Anthracotic index (AI) was defined as the absolute absorbance by densitometry. The histopathological diagnosis was concluded according to Noguchi's classification for small-sized pulmonary adenocarcinoma. The mean AI and the frequency of p16(ink4a) gene aberrant methylation of heavy smokers were significantly higher than that of nonsmokers (Ｐ<0.01 andＰ<0.05, respectively). The frequency of p16(ink4a) gene aberrant methylation of early stage small-sized adenocarcinoma was lower than that of advanced and poorly differentiated, while p16(ink4a) protein expression level of early stage small-sized adenocarcinoma was significantly higher than that of poorly differentiated small-sized adenocarcinoma (P<0.05).

Conclusions: AI and p16(ink4a) gene aberrant methylation may provide a potential universal biomarker for small-sized adenocarcinoma.