Mouse mammary tumour virus-like virus (MMTV-LV) is present within the liver in a wide range of hepatic disorders and unrelated to nuclear p53 expression or hepatocarcinogenesis.

BACKGROUND/AIMS: The human equivalent of mouse mammary tumour virus (MMTV-LV) may have a role in the pathogenesis of primary biliary cirrhosis (PBC) and breast carcinogenesis. We investigated MMTV-LV prevalence in patients with liver disease of diverse aetiology and associations with hepatic expression of hormonal receptors, p53 protein and complicating hepatocarcinogenesis.
METHODS: Nested PCR for MMTV-LV envelope was performed using tissue from 210 patients with liver disease and 20 patients with histologically normal liver. Hepatic expression of estrogen receptor-alpha (ER-alpha), progesterone receptor (PgR) and p53 protein was determined by immunohistochemistry. MMTV-LV expression was also determined in hepatocellular carcinoma (HCC) tissue from 21 patients, in 11 of whom paired non-tumourous liver tissue was available for comparison.
RESULTS: MMTV-LV envelope sequences were present in 25% (53/210) of liver disease biopsies but not in histologically normal liver (0/20) (P=0.02). There was no association between MMTV-LV presence and hepatic expression of ER-alpha or p53 protein. No liver sections were PgR positive. MMTV-LV prevalence was not significantly different in HCC tissue, paired non-tumourous chronic liver disease tissue from the same patients and liver disease tissue from patients without complicating HCC.
CONCLUSIONS: Hepatic expression of MMTV-LV is evident in a wide range of non-cirrhotic and cirrhotic liver diseases, irrespective of ER-alpha, PgR or p53 status, and unrelated to complicating HCC.