A Multicenter Study for Evaluating the Benign and Malignant Pulmonary Noldules by Detecting the Epigenetic Imprinting Alterations in Bronchoalveolar Lavage

Bronchial biopsy and bursh are widely used in lung cancer diagnosis but not bronchoalveolar lavage because of its low sensitivity. As the molecular alterations usually occur before the morphological changes, genetic and epigenetic biomarkers will be helpful for early diagnosis of cancers. As an important epigenetic regulation in mammalian embryo development, genomic imprinting plays important roles in cancers. In normal post-natal somatic cells, imprinted genes are "silenced", that is mono-allelically expressed either from the maternal or paternal allele, while in cancers, some silenced imprinting genes' copies could be reactivated, leading to expressions from both alleles. The loss of monoallelic gene regulation is named loss of imprinting (LOI), and has been previously found in various human cancers. Our previous studies has identified several imprinted genes with elevated aberrant allelic expressions in lung cancer. A diagnostic model based on the epigenetic imprinting biomarkers achieved 99.1% sensitivity and 92.1% specificity. In this study, we will first verify the epigenetic imprinting biomarkers in bronchoalveolar lavage, and refine the previously developed diagnostic model specifically for lavage samples. The diagnostic model will be independently validated in a group of prospectively enrolled cases. This study will help to distinguish benign and malignant pulmonary nodules presurgically, and improve the early diagnosis of lung cancer.