Genomic Mutations of Primary and Metastatic Lung Adenocarcinoma in Chinese Patients

Lung cancer is still the leading cause of cancer-related death worldwide. Of lung cancer, lung adenocarcinoma (LUAD) is the most common subtype. Most patients with LUAD would develop into metastasis, which limits the available treatment. Targeted therapy and immunotherapy provided options for those advanced patients. But they also broached up challenges to identify the appropriate patients. This study aims to reveal the landscapes of genomic mutations in primary and metastatic LUAD and their actionability. This study enrolled 636 patients with LUAD, of whom 85 and 551 were from patients with and without metastasis, respectively. Next-generation sequencing technology was used to retrieve their genomic information. Genomic mutations including short nucleotide variation, long variation, copy number variations, and fusions were called. The corresponding actionability was revealed. A comparison of genomic mutations and actionability between primary and metastatic LUAD was performed. In primary tumors, BRCA2 and FAT3 were significantly mutated in older patients; while in metastases, ALK and NOTCH2 were significantly mutated in younger patients. Primary tumors in male patients were significantly mutated in LRP1B and KRAS. Compared to primary tumors, metastases harbored less short nucleotide variations but more copy number variations and fusions. In metastases, chromosome 1 and chromosome 9 had less short nucleotide variations and more CNV than in primary tumors. Genomic variations of activated dendritic cells were more frequently mutated in metastases. EGFR genomic variations were negatively associated with PD-L1 and TMB. Patients with EGFR inhibitor treatment tend to have lower PD-L1 expression. The revealed discrepancy between primary and metastatic lung cancer could help guide the treatment strategies and the development of novel drugs.