Association between Epstein-Bar virus and colorectal cancer: A systematic review and meta-analysis.

AIM: This study aimed to investigate the prevalence and any potential association between Epstein-Barr virus (EBV) infection and colorectal cancer (CRC). METHODS: A systematic literature search was performed by finding relevant cross-sectional and case-control studies from main online databases. Heterogeneity, odds ratio (OR), and corresponding 95% confidence interval (CI) were applied to all studies through meta-analysis and forest plots. The analysis was performed using STATA Software v.14.1. RESULTS: Twenty-three articles were included in the meta-analysis, eight of them were case/control and 15 were cross-sectional. The pooled prevalence of EBV among 1954 CRC patients was 18% (95% CI: 12%-26%; I2 = 93.14%). Furthermore, in geographical regions, the highest and lowest prevalence of EBV was observed in South America 30% (95% CI: 18%-43%) and Africa 0% (95% CI: 0%-5%), respectively. An association was found between EBV infection and CRC [OR = 3.4 (95% CI (1.13-10.27); I2 = 72.3%)]. CONCLUSION: EBV infection is associated with CRC and can be considered a potential risk factor for the development of CRC. Although the exact molecular mechanism of EBV infection in the development of CRC is still unknown, it seems that latent infection by EBV, intestinal damage, and inflammation can be important factors in the induction of CRC.

Association between human polyomavirus infection and brain cancer: A systematic review and meta-analysis.

AIM: The aim of this study was to investigate the prevalence and potential association between the infection with some members of the polyomaviridae family of viruses and development of the brain tumors. METHODS: A systematic literature search was performed by finding relevant cross-sectional and case-control studies from a large online database. Heterogeneity, OR, and corresponding 95% CI were applied to all studies by meta-analysis and forest plots. The analysis was performed using Stata Software v.14. RESULTS: Twenty-three articles (33 datasets) were included in the meta-analysis, four (four datasets) of which were case/control studies and the rest were cross-sectional. The pooled prevalence of polyomaviruses among brain cancer patients was 13% (95% CI: 8-20%; I2 = 96.91%). In subgroup analysis, the pooled prevalence of JCV, SV40, BKV and Merkel cell polyomavirus was 20%, 8%, 6%, and 16%, respectively. An association was found between polyomavirus infection and brain cancer [summary OR 7.22 (95% CI (2.36-22.05); I2 = 0%)]. The subgroup analysis, based on the virus type, demonstrated a strong association between JCV infection and brain cancer development [summary OR 10.34 (95% CI 1.10-97.42; I2 = 0%)]. CONCLUSION: The present study showed a significant association between polyomavirus infection and brain tumors. Moreover, these results suggest that polyomavirus infection may be a potential risk factor for the development of brain cancer.