NT5E and hepatocellular carcinoma: Immunohistochemistry study of CD73 expression in normal and hepatobiliopancreatic tissues;CD73 expression is present in all HCC, staining for CD73 ranges from intensity of 1+ to 3+ with a median intensity of 2+;Aberrant membranous and/or high/strong cytoplasmic expression for CD73 is seen in invasive HCC