Liver cancers are strongly linked to hepatitis B virus (HBV) and hepatitis C virus (HCV). Egypt has the highest prevalence of HCV worldwide and has rising rates of hepatocellular carcinoma (HCC). Egypt's unique nature of liver disease presents questions regarding the distribution of HBV and HCV in the etiology of HCC. Accordingly, a systematic search of MEDLINE, ISI Web of Science, ScienceDirect and World Health Organisation databases was undertaken for relevant articles regarding HBV and HCV prevalence in Egypt among healthy populations and HCC cases. We calculated weighted mean prevalences for HBV and HCV among the populations of interest and examined differences in prevalence by descriptive features, including age, year and geographic region. Prevalences for HBV and HCV were 6.7% and 13.9% among healthy populations, and 25.9% and 78.5% among HCC cases. Adults had higher prevalences of both infections (Adult HBV 5 8.0%, Child HBV 5 1.6%; Adult HCV 5 15.7%, Child HCV 5 4.0%). Geographically, HBV was higher in the south, whereas HCV was greater in the north (North HBV 5 4.6%, South HBV 5 11.7%; North HCV 5 15.8%, South HCV 5 6.7%). Among HCC cases, HBV significantly decreased over time (p 5 0.001) while HCV did not, suggesting a shift in the relative influences of these viruses in HCC etiology in Egypt. Our results highlight large amounts of heterogeneity among the epidemiological factors associated with liver disease in Egypt and underscore the necessity of an integrated strategy for the successful prevention of viral hepatitis infections and chronic liver disease. ' 2008 Wiley-Liss, Inc.Key words: pooled analysis; liver cancer; infectious diseases; developing countries Hepatocellular carcinoma (HCC) comprises nearly 6% of all incident cancer cases worldwide, with the overwhelming majority occurring in the developing world.1 One of the least curable malignancies, HCC is the third most frequent cause of cancer mortality among men worldwide.1 Chronic infection with hepatitis B virus (HBV) and hepatitis C virus (HCV) have been cited as, by far, the most important etiologic agents.2 According to the World Health Organisation (WHO), 350 million people are chronically infected with HBV and 170 million are infected with HCV.3,4 The relative importance of HBV and HCV as causative agents can vary greatly from region to region and over time.1,5 Selecting appropriate HCC prevention and control methods, therefore, depends on understanding the dynamics of these agents in a specified geographic region.Incidence of HCC in Egypt is currently increasing, which may be the result of a shift in the relative importance of HBV and HCV as primary risk factors.6-8 HCC is the second most frequent cause of cancer incidence and mortality among men in Egypt.9 Hospitalbased studies from Egypt have reported an increase in the relative frequency of all liver-related cancers in Egypt (>95% as HCC), from 4.0% in 1993 to 7.3% in 2003.6-8 The Middle East Cancer Consortium recently reported that the incidence rate among males was 7 times greater...