HCC tissue differs histopathologically from normal and adenomatous liver tissue but has no difference in vector genome copy number. Hematoxylin and eosin–stained sections for histopathologic diagnosis of (A) normal liver; (B) hepatic adenoma, arrows denote zone of compression between adenoma and normal liver; and (C) hepatocellular carcinoma, arrows indicate mitotic figures. Images were captured with the use of a Zeiss Axiophot microscope (Carl Zeiss Imaging, Inc) with a 20×, 0.40 aperture EC PLAN NEOFLUAR objective lens at room temperature. Images were acquired with the use of an Olympus DP70 (Olympus America Inc) camera and DP Manager Version 1.21.107 software, with subsequent image cropping performed with Adobe Photoshop. (D) AAV2-hFIX16 vector genome copy number in tumor and normal liver was quantified by qPCR, performing 3 independent measurements on total DNA isolated from tumor and normal liver tissue. P values from 2-tailed Student t test between 3 independent measurements of adjacent normal liver tissue and tumor tissue.