Comprehensive characterization of genomic and radiologic features reveals distinct driver patterns of RTK/RAS pathway in ground-glass opacity pulmonary nodules.

Abstract

Ground-glass opacity (GGO)-associated pulmonary nodules have been known as a radiologic feature of early-stage lung cancers and exhibit an indolent biological behavior. However, the correlation between driver genes and radiologic features as well as the immune microenvironment remains poorly understood. We performed a custom 1021-gene panel sequencing of 334 resected pulmonary nodules presenting as GGO from 262 Chinese patients. A total of 130 multiple pulmonary nodules were sampled from 58 patients. Clinical-pathologic and radiologic parameters of these pulmonary nodules were collected. Immunohistochemistry (IHC) and multiplex immunofluorescent staining (mIF) were applied to analyze proliferation and immune cell markers of GGO-associated pulmonary nodules. Compared with pure GGO nodules, mixed GGO nodules were enriched for invasive adenocarcinoma (IAC) (182/216 vs 73/118, P < .001). Eighty-eight percent (294/334) of GGO-associated nodules carried at least one mutation in EGFR/ERBB2/BRAF/KRAS/MAP2K1 of the RTK/RAS signaling pathway, and the alterations in these driver genes were mutually exclusive. The analysis of multifocal pulmonary nodules from the same patient revealed evidence of functional convergence on RTK/RAS pathways. Nodules with ERBB2/BRAF/MAP2K1 mutations tended to be more indolent than those with EGFR and KRAS mutations. IHC and mIF staining showed that KRAS-mutant GGO nodules displayed higher infiltration of CD4+ T cell and CD8+ T cell as well as stronger proliferation and immune inhibitory signals. Our study demonstrates a driver landscape of radiologically detectable GGO-associated pulmonary nodules in Chinese patients and supports that different driver patterns in RTK/RAS pathway are corresponding to different radiologic features.