Evaluates the carcinogenic risk to humans posed by exposure to three
hepatotropic viruses: hepatitis B virus, hepatitis C viruses, and the
hepatitis D virus, which exists as a satellite agent of hepatitis B
virus.
Among the several viruses that can cause hepatitis, these three were
selected for evaluation because of their potential to induce chronic
liver infection. The most extensive monograph evaluates the large body
of data suggesting a link between infection with hepatitis B virus and
hepatocellular carcinoma in humans. The evaluation takes on particular
importance in view of the high prevalence of chronic infection with this
virus, particularly in developing countries. A brief summary of the
structure of the virus and methods for its detection and analysis is
followed by a thorough assessment of human exposure data, including
patterns of transmission and factors influencing the course and clinical
manifestations of infection, studies of cancer in humans, and studies of
cancer in primates, transgenic mice, woodchucks, ground squirrels, ducks
and other species. In view of the strong association between
hepatocellular carcinoma and chronic infection with the hepatitis B
virus demonstrated in numerous studies, the monograph concludes that
chronic infection with hepatitis B virus is carcinogenic to humans. The
second monograph evaluates data on hepatitis C virus, which is the
etiological agent in most cases of post-transfusion hepatitis. Following
a similar format of evaluation, the monograph concludes that chronic
infection with hepatitis C virus is carcinogenic to humans. The final
monograph evaluates data on hepatitis D virus, a satellite agent of
hepatitis B virus with no known natural host other than humans. Because
of methodological problems and inconsistencies in the evidence,
infection with hepatitis D virus could not be classified as to its
carcinogenicity to humans.
