Hepatocellular carcinoma (HCC) is a prevalent cancer in sub-Saharan Africa and eastern Asia. Hepatitis B virus and aflatoxins are risk factors for HCC, but the molecular mechanism of human hepatocellular carcinogenesis is largely unknown. Abnormalities in the structure and expression of the tumour-suppressor gene p53 are frequent in HCC cell lines, and allelic losses from chromosome 17p have been found in HCCs from China and Japan. Here we report on allelic deletions from chromosome 17p and mutations of the p53 gene found in 50% of primary HCCs from southern Africa. Four of five mutations detected were G----T substitutions, with clustering at codon 249. This mutation specificity could reflect exposure to a specific carcinogen, one candidate being aflatoxin B1 (ref. 7), a food contaminant in Africa, which is both a mutagen that induces G to T substitution and a liver-specific carcinogen.

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Of approximately 360 million people in the world chronically infected with hepatitis B virus (HBV), 65 million reside in Africa. Thus, Africa, with 12% of the world's population, carries approximately 18% of the global burden of HBV infection, with hepatocellular carcinoma and cirrhosis accounting for 2% of the continent's annual deaths. Despite HBV being endemic or hyperendemic in Africa, there is a paucity of data on the genotypes and their distribution. Genotype A is found mainly in southern, eastern and central Africa. Most African genotype A strains belong to subgenotype A1, with subgenotype A3 found in western Africa. Genotype D prevails in northern countries and genotype E in western and central Africa. Ithas become increasingly evident that heterogeneity in the global distribution of HBV genotypes may be responsible for differences in the clinical outcomes of HBV infections and the response to antiviral treatment and vaccination. A limited number of studies have been published relating genotypes to clinical outcomes in African countries. Because observations from other regions of the world can not be extrapolated from one locale to another, the HBV strains circulating in Africa should be studied and related to clinical outcomes.

The WHO global health sector strategy on viral hepatitis, created in May, 2016, aims to achieve a 90% reduction in new cases of chronic hepatitis B and C and a 65% reduction in mortality due to hepatitis B and C by 2030. Hepatitis B virus (HBV) is endemic in sub-Saharan Africa, and despite the introduction of universal hepatitis B vaccination and effective antiviral therapy, the estimated overall seroprevalence of hepatitis B surface antigen remains high at 6·1% (95% uncertainty interval 4·6-8·5). In this Series paper, we have reviewed the literature to examine the epidemiology, burden of liver disease, and elimination strategies of hepatitis B in sub-Saharan Africa. This paper reflects a supranational perspective of sub-Saharan Africa, and recommends several priority elimination strategies that address the need both to prevent new infections and to diagnose and treat chronic infections. The key to achieving these elimination goals in sub-Saharan Africa is the effective prevention of new infections via universal implementation of the HBV birth-dose vaccine, full vaccine coverage, access to affordable diagnostics to identify HBV-infected individuals, and to enable linkage to care and antiviral therapy.