Correlation of DEPDC5 rs1012068 and rs5998152 Polymorphisms with Risk of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Background Emerging evidence has shown that two common genetic polymorphisms within the pleckstrin domain-containing protein 5 (DEPDC5), rs1012068 and rs5998152, may be associated with the risk of hepatocellular carcinoma (HCC), especially in those individuals chronically infected with the hepatitis C virus (HCV) or the hepatitis B virus (HBV). However, these findings have not been consistently replicated in the literature due to limited sample sizes or different etiologies of HCC. Thus, the present systematic review and meta-analysis were performed to resolve this inconsistency. Methods The databases PubMed, Embase, Web of Science, the China National Knowledge Infrastructure, and Scopus were searched up to December 12, 2022. Data from relevant studies were pooled, and odds ratios and 95% confidence intervals were calculated. Results A total of 11 case-control studies encompassing 2,609 cases and 8,171 controls on rs1012068 and three encompassing 411 cases and 1,448 controls on rs5998152 were included. Results indicated that the DEPDC5 rs1012068 polymorphism did not significantly increase HCC risk in the total population (allelic model (OR = 1.32, 95% CI = 1.04–1.67, P = 0.02); the recessive model (OR = 1.42, 95% CI = 0.96–2.10, P = 0.08); the dominant model (OR = 1.43, 95% CI = 1.09–1.87, P = 0.01); the homozygous model (OR = 1.61, 95% CI = 1.01–2.57, P = 0.05); the heterozygous model (OR = 1.39, 95% CI = 1.09–1.79, P = 0.009)). Subgroup analyses based on ethnicity and etiology revealed that the rs1012068 polymorphism, under all five genetic models, was associated with increased HCC risk in Asians or in individuals with chronic HBV infection but not in individuals with chronic HCV infection. A significant association was also observed between rs5998152 and HCV-related HCC risk in Asians chronically infected with HCV under allelic, dominant, and heterozygous models. Conclusion Our study suggests that the DEPDC5 rs1012068 polymorphism increases HCC risk, especially in Asians with chronic HBV infection, while the rs5998152 polymorphism increases HCC risk in Asians with chronic HCV infection.


Introduction
Liver cancer is the ffth most common cancer and the fourth leading cause of cancer-related death worldwide. Among men, it is the fourth most frequent cancer and the second leading cause of cancer-related deaths [1]. Hepatocellular carcinoma (HCC) accounts for 75%-85% of cases of primary liver cancer worldwide [2]. Te main risk factors for HCC are chronic infection with the hepatitis B virus (HBV) or hepatitis C virus (HCV), afatoxin-contaminated foods, heavy alcohol intake, excess body weight, type 2 diabetes, and smoking. Besides these etiological factors, increasing evidence has revealed that host genetic variations, including single-nucleotide polymorphisms (SNPs), might also play a role in HCC development and progression.
Pleckstrin domain-containing protein 5 (DEPDC5) has been implicated in focal epilepsy, brain malformation, and sudden unexplained death in epilepsy [3][4][5]. DEPDC5 may be a target to treat epilepsy because it negatively regulates amino acid sensing through the signaling pathway involving the mammalian target of rapamycin complex 1 (mTORC1) [6,7]. DEPDC5 also negatively regulates the AKT-mTORC1 pathway, so its agonists may be useful against the activation of latent HIV-1 infection [8]. DEPDC5 may participate in a signaling pathway in which Pim1 and Akt act via mTORC1 to promote the proliferation and survival of cancer cells [9]. Downregulation of DEPDC5 leads to upregulation of matrix metalloprotease 2 through the β-catenin pathway, which may contribute to HCV-related fbrosis [10]. Such downregulation also renders HCC tumors more resistant to reactive oxygen species under the leucine-depleted conditions of chronic liver disease, contributing to poor patient outcomes [11].
Tese contradictory results may refect the relatively small samples in individual studies, heterogeneity among control populations, and diferent HCC etiologies. We conducted the present systematic review and meta-analysis to clarify the relationship of DEPDC5 polymorphisms rs1012068 and rs5998152 with HCC risk. We also performed subgroup analyses based on ethnicity and the etiology of HCC.

Search Strategy.
Tis meta-analysis complied with "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guidelines [24]. A comprehensive search for relevant studies was performed in the PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, and Scopus databases from their inception through December 12, 2022. Te following terms were used: "genetic polymorphism" or "single-nucleotide polymorphism" or "polymorphism" or "SNP" or "mutation" or "variation" or "variant," or "liver tumor" or "liver cancer" or "hepatocellular carcinoma" or "liver neoplasms," and "DEP domain containing 5" or "DEPDC5" or "rs1012068" or "rs5998152." Tere were no language restrictions. Additional studies were identifed through manual searching of references in original or review articles on this topic. If there was a duplication of published literature by the same research group, the study with the larger sample was selected. Any disagreements were resolved by discussion.

Data Extraction.
Te data from the included studies were extracted by two independent investigators. Discrepancies during data extraction were resolved by a third investigator. Te extracted information included the frst author's surname, publication year, country in which the study was conducted, ethnicity, cohort characteristics of the cases and controls, the total number of patients in the case and control groups, the number of subjects with each genotype, and matched parameters between cases and controls.

Assessment of Methodological Quality.
Quality assessments of the eligible studies were performed using the Newcastle-Ottawa Scale (NOS) [25]. Te NOS involves a total of 9 items, each of which has a score that ranges from 1 to 9. A NOS score of 5 points or above would be classifed as a high-quality study, while a NOS score of 4 points or below would be classifed as a poor-quality study [26].

Characteristics of Primary
Studies. Te fowchart of study selection is summarized in Figure 1, and search strategies for each database are presented in Table S1. After a comprehensive search of the databases using the search strategies in Table S1, 54 relevant studies were compliant with the search strategy, of which 28 were excluded due to being duplicates. Another 11 were omitted after screening titles and abstracts. Among the 15 studies remaining, one was a case-only study [27], one investigated fbrosis but not HCC [10], and two were based on the same participants [19,28]. Eventually, 12 studies were included in the current meta-analysis (Table 1). No relevant case-control studies were identifed based on the alternative polymorphism IDs for rs1012068 (rs56511012, rs58339834, rs386510025) or for rs5998152 (rs61578881, rs8143107).

Sensitivity Analysis.
Te controls in all 8 case-control studies that investigated the association between the rs1012068 polymorphism and HCC risk were chronically infected with HCV, except the controls in one study [20], in which the controls were healthy individuals. To eliminate such heterogeneity among controls, we repeated the metaanalysis after deleting this study. Repeating the metaanalysis led to similar results as when the study was included, suggesting that our meta-analysis is reliable ( Figure S3). Figures 5 and 6, Begg's funnel plot and Egger's regression test showed that the metaanalysis of rs1012068 and rs5998152 polymorphisms showed no obvious asymmetry under the fve genetic models (all P > 0.05).

Discussion
In the case of rs1012068, an overall meta-analysis of the total population indicated a signifcant association with increased HCC risk, regardless of HCC etiology and source of controls. Subgroup analysis based on ethnicity supported this association for Asians. Subsequently, meta-analyses of individuals chronically infected with HBV or HCV were performed. Te cases and controls in three case-control studies [14,16,19] were all chronically infected with HBV, and in this uniform sample, results showed that the rs1012068 polymorphism signifcantly increased HCC risk in individuals with chronic HBV infection. In contrast, the association between the rs1012068 polymorphism and HCV-related HCC risk was not signifcant.
In the case of rs5998152, three case-control studies examined a potential relationship between this polymorphism and the risk of HCV-related HCC [12,15,23]. All cases and controls were chronically infected with HCV. Results showed the rs5998152 polymorphism was signifcantly associated with HCC risk in Asians with chronic HCV infection under allelic, dominant, and heterozygous models.
It may be that these polymorphisms weaken the activity of DEPDC5, preventing it from inhibiting mTORC1 as it does normally, which in turn leads to pathogenic infammation and cell growth in the liver [22,29]. Future research should explore how the rs1012068 and rs5998152 polymorphisms afect DEPDC5 expression and activity.
Although positive results were obtained, some limitations that may afect the interpretation of the meta-analysis were presented in this work. First, samples were relatively small due to the lack of case-control studies, especially for rs5998152. Second, among studies investigating the association between the rs1012068 polymorphism and HCC risk, the controls in all casecontrol studies except one [20] were chronically infected with HCV. When one study with healthy controls was deleted from the meta-analysis [20], the results were not substantially altered, suggesting that our meta-analysis is reliable. Tird, the included studies in our meta-analysis spanned 2011-2022, during which antiviral treatments have improved and been widely used for treating HCV-or HBV-related liver disease [30,31]. Since the included studies did not report detailed data on the use of such therapies, further research should explore how they infuence the risk of HCC in individuals with DEPDC5 polymorphisms. Fourth, the robustness of the current meta-analysis may be reduced because the case-control studies involved used diferent genotyping methods that may difer in sensitivity and specifcity, and potentially by other confounding factors such as age, sex, alcohol intake, and tumor status. Given these various limitations, the fndings of our meta-analysis should be validated and extended in large, well-designed studies.
In summary, our study suggests that the DEPDC5 rs1012068 polymorphism increases HCC risk, especially in Asians with chronic HBV infection, while the rs5998152 polymorphism increases HCC risk in Asians with HCV infection. Further large, well-designed studies are required to validate these fndings.    Test for overall efect: Z = 4.05 (P < 0.0001) Heterogeneity: chi 2 = 3.91, df = 2 (P = 0.14); I 2 = 49%

Data Availability
Te data used to support the fndings of this study are included within the article.

Conflicts of Interest
Te authors declare that they have no conficts of interest.

Authors' Contributions
Shaoliang Zhu, Zhenyong Tang, and Mengjie Zou contributed equally to this work.