BACKGROUND: Hepatocellular carcinoma (HCC) is a highly aggressive neoplasm that usually originates from liver cells and is one of the most common malignancies worldwide. To improve the survival rate of HCC patients, specific prognostic markers are essential to guide HCC therapy. CEP55 is a microtubule-bundling protein involved in critical cell functions, including cell growth, transformation, and cytokinesis. AIMS: This study examined gene alterations in HCC tumor tissues through comprehensive analysis, aiming to elucidate their contribution to disease development. METHODS: Bioinformatics tools were employed to investigate the expression, genetic variations, prognostic significance, and clinicopathological relevance of CEP55 across GEO and TCGA datasets. We further explored gene alterations, DNA methylation levels, and immune infiltration of CEP55. To elucidate the potential molecular mechanisms involved, GO and KEGG analysis was performed. Finally, RT-qPCR was also performed on a number of normal and tumoral cell lines in vitro, which demonstrated that the expression of the CEP55 was significantly higher in the tumor cell lines. RESULTS: We observed that CEP55 was upregulated in 16 cancers compared to corresponding normal tissues. CEP55 was found to be related to T stages, pathologic stages, histologic grade, and levels of AFP. K-M analysis demonstrated that CEP55 expression was associated with a worse outcome. ROC curve analysis showed that CEP55 expression accurately distinguished HCC from normal tissue (AUC = 0.954). The area under 1-,3- and 5-year survival ROCs were above 0.6. The HSPA4 genetic alterations in HCC were 0.8%. Among the 15 DNA methylation CpG sites, 6 were related to the prognosis of HCC. HSPA4 was positively related to immune cell infiltration and immune checkpoints in HCC. The KEGG pathway analysis indicated that CEP55 was associated with the cell cycle and presented together with CDK1. HCC cell lines were demonstrated to express high levels of CEP55 compared to normal cells. CONCLUSION: As a result of bioinformatic analyses and RT-qPCR validation in HCC, CEP55 increased in HCC tissues and was associated with the stage of the disease and survival rate.