Abstract
BACKGROUND: Multifocal lung cancers (MLCs) are common in patients newly diagnosed with lung cancer, and histological results of most synchronous MLCs are similar. Few cases with different histology findings have been reported, and no genomic or transcriptomic profiling of this kind of cases were done before. Here, we analyzed genomic and transcriptomic profiles of all lung tumors from 2 patients with synchronous adenocarcinoma and squamous cell carcinoma in the same lung lobe. CASE PRESENTATION: Two patients were diagnosed as synchronous adenocarcinoma and squamous cell carcinoma and underwent surgical resection. All 4 tumors showed distinct genomic profiles, therefore were independent primary tumors. Several cancer-associated pathways, such as RTK-RAS pathway and Notch pathway, exhibited different mutated genes in different tumors from the same patient. Several known cancer genes with different mutations, including TP53 and KEAP1, were also detected. Mutation signature analysis demonstrated that the tumor initiation might be related to the transcription coupled nucleotide excision repair process. Two tumors for these 2 patients had loss of heterogeneity (LOH) in HLA genes, showing tumor escaping mechanism. Furthermore, tumor microenvironments showed different patterns in 2 tumors from the same patient. The tumor with more neoantigens and no HLA LOH showed more infiltrating CD8+ T cells and more clonal TCRs, indicating a more active microenvironment. CONCLUSIONS: The lung squamous cell carcinoma and lung adenocarcinoma form the same patient are from independent origins. The genetic profiles and transcriptomic microenvironments are quite different for these 2 tumors. With the same genetic background, the 2 tumors in one patient exhibited different tumor escape mechanisms and immune responses, including HLA LOH and T cell infiltrating and expansion.