Research Communications of the 27(th) ECVIM-CA Congress: Intercontinental, Saint Julian's, Malta, 14th to 16th September 2017

Disclosures: No disclosures to report. Canine chronic hepatitis (CCH) is characterized histologically by hepatocellular apoptosis or necrosis, a variable mononuclear or mixed inflammatory infiltrate, regeneration and fibrosis. Lifeexpectancy following diagnosis is unpredictable, ranging from days to years. Reported prognostic indicators (hyperbilirubinemia, hypoalbuminemia and presence of ascites or cirrhosis) are unreliable, particularly in end-stage disease. Hepatocyte expression of p21, a universal cell-cycle inhibitor and marker of cellular senescence, is strongly negatively correlated with outcome in humans with alcoholic and non-alcoholic related liver disease and is a better prognostic marker than histological or clinical scoring systems. P21 expression has not been investigated in CCH. This study investigated whether hepatocyte p21 expression is increased in CCH and if expression is associated with survival. Cases of CCH were retrieved from the pathology database (2004) (2005) (2006) (2007) (2008) (2009) (2010) (2011) (2012) (2013) (2014) (2015) (2016) and liver biopsy samples were reviewed using routine stains (hematoxylin & eosin, rhodanine, and Sirius red). Immunohistochemistry was performed using monoclonal mouse anti-human p21 on all selected cases and four control liver samples with normal histology and no history of liver disease. P21 expression was manually quantified by scoring p21-positive and p21-negative hepatocytes in eight high-power fields for each case by two blinded observers and expressed as a percentage of total hepatocyte number. Kendall's Tau correlation coefficients were used to assess relationships between p21 expression and survival time or age; significance was set at P < 0.05 (2 tailed).