Enhancer RNA in cancer: identification, expression, resources, relationship with immunity, drugs, and prognosis

Enhancer RNA (eRNA), a type of non-coding RNA transcribed from enhancer regions, serves as a class of critical regulatory elements in gene expression. In cancer biology, eRNAs exhibit profound roles in tumorigenesis, metastasis, and therapeutic response modulation. In this review, we outline eRNA identification methods utilizing enhancer region prediction, histone H3 lysine 4 monomethyl chromatin signatures, and nucleosome positioning analysis. We quantitate eRNA expression through RNA-seq, single-cell transcriptomics, and epigenomic integration approaches. Functionally, eRNAs regulate gene expression, protein function modulation, and chromatin modification. Key databases detailing eRNA annotations and interactions are highlighted. Furthermore, we analyze the connection of eRNA with immune cells and its potential in immunotherapy. Emerging evidence demonstrates eRNA's critical involvement in immune cell crosstalk and tumor microenvironment reprogramming. Notably, eRNA signatures show promise as predictive biomarkers for immunotherapy response and chemoresistance monitoring in multiple malignancies. This review underscores eRNA's transformative potential in precision oncology, advocating for integrated multiomics approaches to fully realize their clinical applicability.