Hepatitis B virus and hepatitis C virus infections and risk of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PADC) represents a highly lethal cancer with a very dismal prognosis. Absence of early symptoms, advanced stage at diagnosis, aggressive biological behaviour and lack of effective systemic treatment are the most important factors, explaining its elevated mortality rate and its low overall five-year survival (< 5%). Until now, the causes of this malignancy remain still largely unknown and further efforts are underway to reach a better knowledge of PADC aetiology and to improve our understanding of mechanisms involved in carcinogenesis of this organ. In the last years it has progressively emerged that viruses play a key role in human carcinogenesis. Unfortunately, some host and viral factors have contributed to make the study of the pancreas extremely difficult and to hamper the identification of pathogenetic processes involved in cancer development, including its retroperitoneal localization as well as the small size of precursor cancer lesions. However, in the past and more recently, some histological investigations suggested that both antigens and genome of hepatitis B (HBV) and hepatitis C (HCV) viruses, two pathogens with well-known high liver tropism and pro-oncogenic properties may be detected also in extra-hepatic tissues, such as pancreas. In addition, some epidemiological articles have suggested that HBV and HCV might be involved even in pancreatic carcinogenesis. Here we review the results of available reports, evaluating the possible association between HBV or/HCV infections and risk of pancreatic cancer development as well as to discuss the limiting factors of these researches.