BackgroundProstate cancer is one of the most common malignancies in men. Members of the elongation of the very-long-chain fatty acid (ELOVL) gene family have been reported to participate in the occurrence and development of various cancers. However, the function of ELOVL gene family members (ELOVLs) in prostate cancer has not been fully elucidated. MethodsThe mRNA expression and prognostic value of ELOVLs in prostate cancer were analyzed using the GEPIA database. The Oncomine database and PrognoScan database were used to further verify the mRNA expression level and prognostic value of ELOVL2 in prostate cancer. RT–qPCR and Western blotting were used to validate the expression levels of ELOVL2 in four prostate cancer cell lines. Immunohistochemistry was performed to detect the ELOVL2 protein expression levels in prostate cancer tissues. Coexpression analysis in the cBioPortal database and enrichment analysis in Kyoto Encyclopedia of Genes and Genomes (KEGG), CCK8, colony formation, and transwell assays were used to identify the functions and mechanisms of ELOVL2. ResultsELOVL2 expression was upregulated in prostate cancer tissues compared with normal tissues. High expression of ELOVL2 indicated a better prognosis in prostate cancer patients. ELOVL2 expression was negatively correlated with Gleason score. Knockdown of ELOVL2 promoted cell proliferation, colony formation, migration, invasion, and the growth of subcutaneous xenografts and activated the PI3K/Akt signaling pathway by downregulating INPP4B, while overexpression of ELOVL2 reversed these effects. In addition, overexpression of INPP4B blocked the promoting effect of sh-ELOVL2 on cell proliferation, colony formation, migration, invasion, and the PI3K/Akt signaling pathway. ConclusionsOur findings suggest that ELOVL2 might be a prognostic biomarker and therapeutic target for prostate cancer.