EPHX4, a member of the epoxide hydrolase family, though its exact enzymatic function related to epoxide regulation is yet to be fully elucidated, seems to be involved in multiple biological processes. It may play a role in lipid metabolism as it was found localized on the surface of lipid droplets in sebocytes, and its depletion increased lipid droplet size and sebaceous lipogenesis [3]. It has also been implicated in several disease-related pathways, especially in cancer [1,2,4].

In cancer research, EPHX4 has shown significant associations. In laryngeal squamous cell carcinoma, it is highly expressed, associated with poor prognosis, and participates in NK cell-mediated cytotoxicity, while also promoting cancer cell proliferation, colony formation, and invasion [1]. In colorectal cancer, its expression is increased, and it promotes the malignant phenotype of CRC cells. EPHX4 along with other EPHX family members was found to be correlated with some clinicopathologic features and overall survival, and was also positively associated with immune-related genes like CD274, CTLA4, HAVCR2, and TIGIT [2]. In pancreatic adenocarcinoma, EPHX4 is highly expressed, associated with patient sex, clinical stage, and lymph node metastasis, and high expression predicts poor survival. Functional experiments showed its tumor-promoting effects [4].

In conclusion, EPHX4 is involved in lipid metabolism and has tumor-promoting roles in multiple cancers such as laryngeal, colorectal, and pancreatic cancers. These findings from various studies contribute to understanding its biological functions and its potential as a therapeutic target in cancer treatment.