Expression and clinical significance of lung‐specific X protein mRNA in bronchial brushing specimens from patients with or without lung cancer

Abstract

The aim of this study was to evaluate the diagnostic utility of lung-specific X protein (LUNX) mRNA expression in bronchial brushing specimens from patients with lung cancer. LUNX mRNA levels were assessed by performing RT-PCR on liquid-based cytology bronchial brushing specimens from patients with lung cancer (n=104) or benign lung disease (n=91). LUNX mRNA expression was significantly more frequent in patients with all carcinomas, squamous cell carcinomas, adenocarcinomas, as well as patients with central, peripheral and diffuse carcinomas (P<0.01), and non-small cell lung carcinomas (P<0.05) compared with patients with benign disease. The diagnostic performance of RT-PCR analysis of LUNX mRNA was significantly better than that of cytology in terms of sensitivity (93.3±4.8% vs 64.4±9.2%), negative predictive value (91.6±6.0% vs 71.1±7.9%) and accuracy (88.7±4.4% vs 81.0±5.5%), whereas specificity (83.5±7.6%) and positive predictive value (86.6±6.3%) were lower than those of cytology (100%). Liquid-based cytology and RT-PCR can be performed to detect LUNX mRNA expression in bronchial brushing specimens, and this technique may be a useful adjunct to cytological diagnosis of lung cancer. The sensitivity of the technique was greater than that of cytology but its lower specificity should be taken into account.