Gene Signatures And Cancer-Immune Phenotypes Based On m6A Regulators In Breast Cancer
Abstract Background: The N6-methyladenosine (m6A) has been considered as a new layer of epitranscriptomic regulation on mRNA processing, stability and translation. However, potential roles of m6A RNA methylation modification in tumor immune microenvironment (TIME) of breast cancer are yet fully understood.Methods: We comprehensively evaluated the genetic variations and transcript expressions of 15 m6A regulators, and clinicopathological features in 1,079 breast cancer samples from The Cancer Genome Atlas (TCGA) database. The mRNA and protein levels of several m6A regulators were validated by RT-qPCR, western blot and immunohistochemistry staining in clinical samples from 39 patients with breast cancer. The prognostic values of m6A regulators were systematically evaluated in different database. We correlated the m6A modification patterns of breast cancer with the immune microenvironment and cancer-immune phenotypes. The m6A regulators-related gene signatures were also analyzed to predict the survival of patients.Results: Some m6A regulators’ CNV events might be potential biomarkers for patient’s stage and prognosis in breast cancer. Major regulators had significantly differential mRNA and protein expression in tumor tissue compared to normal samples among different molecular subtypes of breast cancer, and especially high expression of m6A readers YTHDF1 and YTHDF3 predicted poor survival. Two clusters of breast cancer patients identified by the 15 m6A regulators’ pattern showed distinct overall survival, immune activation status and immune cell infiltration. The profiles of these two clusters accorded with that of two classical cancer-immune phenotypes, immune-excluded and immune-inflamed phenotypes. Moreover, the m6A phenotype-related gene signatures could also be survival predictor in breast cancer.Conclusions: The m6A regulators-based patterns might serve as crucial mediators of TIME in breast cancer. Comprehensive evaluation of tumor m6A modification pattern will contribute to enhance our understanding of the characterization of immune cell infiltration in the tumor microenvironment and promote the responsiveness of breast cancer to immunotherapy.