Expression of bromodomain-containing 4 in nasopharyngeal carcinoma: Clinicopathology, prognosis, immunity, and regulatory networks

Objectives: Nasopharyngeal carcinoma (NPC) is a highly aggressive, insidious, recurrent, and metastatic head-and-neck malignancy with a poor prognosis. Bromodomain-containing 4 (BRD4) was upregulated in various tumors and was associated with poor prognosis. Therefore, this study aimed to investigate the biological function of BRD4 in NPC and the molecular mechanisms of expression regulation. Materials and Methods: Based on biological big data, the expression, clinical significance, and possible biological functions of BRD4 in head-and-neck cancer were explored by bioinformatics. Then, based on a tissue microarray containing a cohort of NPC, BRD4 protein expression was detected by immunohistochemistry to explore its clinical significance and impact on prognosis. Statistical analysis: A p-value less than 0.05 was considered as significant. Results: BRD4 expression was upregulated in NPC and positively correlated with metastasis, higher tumor grades, and clinical stages, which might be positively correlated with copy number variation, CD4+ T cells, and immune checkpoint suppressor genes. Moreover, the sensitivity of cancer cells to paclitaxel and gemcitabine was negatively correlated with BRD4 expression. In addition, immunohistochemical staining showed that BRD4 was overexpressed in NPC tissues, which was correlated with lymph node metastasis and poor clinical outcomes. Conclusions: BRD4 is highly expressed in NPC tissues and is associated with a poor prognosis. Its aberrant expression may be closely linked to alterations in the immune microenvironment and chemotherapeutic resistance. Moreover, BRD4 is not only an oncogene in NPC but also a potential therapeutic target.