Defining the cellular and molecular identities of histologic subtypes in lung adenocarcinoma

BACKGROUND: Tumor histology reflects disease aggressiveness and clinical outcomes in cancer patients. Lung adenocarcinomas (LUADs) are classified based on predominant histologic patterns, including high-grade micropapillary and solid subtypes which portend unfavorable clinical features and prognosis. However, the cellular and molecular characteristics underlying these histologic subtypes remain largely unknown. METHODS: We used scRNA-seq to profile 117,266 cells from 18 treatment-naïve LUADs with heterogeneous histologic patterns and also performed spatial transcriptomic analysis (10x Visium) for representative cases. By integrating single-cell transcriptomics with spatial information, we aimed to characterize the cellular identity and spatial organization driving LUAD heterogeneity. RESULTS: T cells in the prognostically unfavorable solid subtype are associated with cancer cell plasticity and promote an immunosuppressive TME. Additionally, we identify HMGA1 as a potential clinically relevant biomarker and therapeutic target for the solid subtype LUAD. CONCLUSIONS: These findings deepen our understanding of the histologic heterogeneity of LUAD and may facilitate the development of subtype-specific biomarkers and targeted therapeutic strategies.