Prognostic implications of CDC45 expression in hepatocellular carcinoma
Abstract Background The outcomes of hepatocellular carcinoma (HCC) remain poor despite dramatic improvements in treatment, and novel prognostic biomarkers are urgently needed to ameliorate the situation. Cell division cycle protein 45 (CDC45) plays a key role in DNA replication, which is considered to be involved in tumorigenesis and has become a new prognostic marker. This study investigated CDC45 expression in tumour tissues and defined its prognostic value in HCC patients. Methods Differential transcriptional and proteomic expression profiles were obtained and validated using multiple datasets. We then used immunohistochemistry (IHC) staining to examine the expression of CDC45 in tumour tissue specimens and compare them with adjacent normal tissue specimens using a constructed tissue microarray (TMA) and analysed the relationship of clinical features and prognosis in HCC patients. Functional enrichment analyses were used to describe significantly involved hallmark pathways of differentially expressed genes (DEGs). Results Contrary to the transcriptome expression level in the database, our results showed that the proteome expression of CDC45 in was evidently downregulated in HCC compared with normal adjacent tissues (P < 0.0001). Although we did not find any differences in terms of vascular invasion, Edmondson grade, lymphatic infiltration, or metastasis between patients with high and low CDC45 expression in our limited number of HCC samples, low expression of CDC45 was significantly correlated with aggressive characteristics, including microvascular invasion (P = 0.046). In addition, a multivariate analysis indicated that CDC45 expression (P = 0.035) was an independent prognostic factor for the overall survival (OS) rate of patients with HCC. Furthermore, patients with low CDC45 expression levels were significantly correlated with inferior OS rates than patients with high CDC45 expression levels (P < 0.05). Functional annotations indicated that CDC45 is involved in the most significant pathways, including the cell cycle, DNA replication, drug metabolism − cytochrome P450, metabolism of xenobiotics by cytochrome P450, and chemical carcinogenesis pathways. Conclusions Our findings showed that a low protein level of CDC45 was associated with a poor prognosis in HCC patients, indicating that CDC45 might be a novel prognostic marker and help identify new therapeutic targets for HCC.