A hepatitis-B like virus, domestic cat hepadnavirus (DCH), has been discovered in cats. In humans and other mammals, similar hepatitis-B viruses are pathogenic, causing acute or chronic hepatitis that can progress to fatal cancer. Importantly, vaccination against hepatitis B viruses prevents disease including liver cancers caused by the virus. In cats, liver cancers are extremely aggressive and their potential causes are unknown. Pilot data from our collaborators identifies DCH detection as a risk factor for primary liver cancer in cats.
The aim of this study is to determine the cellular location of DCH in hepatitis and in primary liver cancers in cats. DNA extracted from retrospective cases of hepatitis, and fixed tissues from biliary carcinoma and hepatocellular carcinoma will be screened for the presence of DCH by conventional PCR. Liver tissue testing positive for DCH by PCR will be examined by in situ hybridization using custom-designed virus probes developed during this study. Age-matched, histologically normal feline liver and unrelated viral probes will be used for controls.
The preferential detection of DCH DNA in the nucleus of neoplastic hepatocytes would strongly support a causal role for DCH in feline liver cancer, and we need the baseline information of whether viral nucleic acid is present in normal or inflamed liver. Any potential outcome of this research would help uncover mechanisms of viral pathogenesis. The ultimate goal of this work is cancer prevention through antiviral treatment and through vaccination to reduce the cat population at risk from liver cancers.