Mutations and expressions of breast cancer 1/2 in lung cancer

Breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) tumor suppressor genes play crucial roles in DNA repair and regulation of transcription. Mutations in these genes are closely associated with the occurrence of cancers. However, the mutation status of BRCA gene in central south Chinese lung cancer patients remains unclear, and its expression levels in lung cancer also need to be further explored.

In this study, we use next-generation sequencing (NGS) technology to analyze the BRCA genes mutations in 462 central south Chinese lung cancer patients. Public databases including cBioportal, Catalogue Of Somatic Mutations In Cancer (COSMIC), The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA) and Expression Profiling Interactive Analysis (GEPIA) are also applied to explore the expression level and mutation status of BRCA in lung cancer patients and their relationships with the prognosis.

We found that the mutation rate of BRCA1/2 in central south Chinese lung cancer patients is 4.3% and 6.5% respectively, and missense mutations account for the majority in both BRCA1/2, which are similar to the international status of BRCA1/2 from public databases. In addition, 45 novel mutations of BRCA1/2 in lung cancer are reported in this study. Furthermore, we find that the BRCA2 mutations are negatively correlated with overall survival rate in lung cancer using cBioportal. Last, we demonstrate that both of the mRNA and protein levels of BRCA1/2 are upregulated in lung cancer, and the elevated mRNA expression levels are positively linked with poor prognosis.

In general, our study better complements knowledge of the BRCA1/2 mutation status in the Chinese lung cancer patients, and firstly reveals the association between BRCA1/2 expression levels and prognosis of lung cancer patients, which may provide great value for the early diagnosis and clinical treatment of lung cancer.