Compared to the vigorous development of targeted drugs and some of them are already become one of the best treatment of choices in lung adenocarcinoma, squamous lung carcinoma has no definite targets and treatment outcome is not yet superior to lung adenocarcinoma. Demonstration of initial carcinogenesis is benefitial in two aspects: cancer prevention and development of its targets. Studying preneoplastic lesions of bronchus can answer those questions. Preneoplastic lesion, which is considered to have malignant potential, may develop into invasive cancer by escaping from host immune response. CD274 (programmed death-ligand 1, PD-L1) interacts with PD-1, is known to inhibit CD8+ cytotoxic T lymphocyte and induce apoptosis and, also to promote the differentiation of CD4+ T cells into regulatory T cells, so finally evade immune surveillance. We hypothesized that PD-L1 may work as an immune evader in preneoplastic lesion during its carcinogenesis. We performed white light and/or autofluorescence bronchoscopy in patients who have risk factor(s) of lung cancer or are suspected to have a lung cancer. Interestingly, PD-L1 was also overexpressed in preneoplastic lesions especially in severe dysplasia of the bronchus. This finding implies overexpression of PD-L1 can involve at early step of carcinogenesis. Further studies are needed to demonstrate the role of PD-L1 in preneoplastic bronchial lesion potential to develop invasive cancer.

Citation Format: Hee Sun Park, Bo Mi Park, Dong Il Park, Chung Jae Uk, Jae Young Moon, Jung Sung Soo, Choong Sik Lee, Ju Ock Kim, Sun Young Kim, Jaseok Peter Koo. Programmed death-ligand 1 is overexpressed in bronchial preneoplastic lesions: can it be a risk indicator. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-092. doi:10.1158/1538-7445.AM2015-LB-092