Bromodomain containing 4 (BRD4) as a potential prognostic marker in a pan-cancer analysis of human tumors

There is some evidence supporting an association between Bromodomain containing 4 (BRD4) and cancer, but no research using pan-cancer analysis has been conducted previously. We therefore investigated the oncogenic role of BRD4 in 33 tumors from the Gene Expression Omnibus and The Cancer Genome Atlas databases. BRD4 is highly expressed in many tumors, and the prognosis of certain cancers is vitally linked with BRD4 expression. BRD4 expression is associated with CD8+ T-cell infiltration levels in testicular germ cell tumors and head and neck squamous cell carcinomas, and we observed a positive relationship between BRD4 and Tcm (T central memory) and Th(T helper) cells, and a negative relationship pDC (plasmacytoid DC). BRD4 had negative associations with marophages, iDC, Treg, cytotoxic cells, and Th17 cells in multiple tumors. The top 100 genes that are most strongly related to BRD4 were identified, and enrichment analysis indicated that the biological process with the closest relationship was chromatin modifying enzymes, related pathways included the signaling pathways of intracellular receptor, cytokine Signaling in Immune system and regulation of TP53 activity through acetylation. BRD4 is related to biological cell behaviors such as DNA-templated transcription, regulation of histone modification, protein modification by small protein removal and mitotic sister chromatid segregation. As the first study to perform a pan-cancer analysis of BRD4, the present findings will improve the understanding of the oncogenic role of BRD4 in different tumors.