Presence of pHP-hF8-X10 mRNA in treated canine liver tissue. (A) Tissue sections stained with a negative control probe showed no signal, indicating that there was no nonspecific staining. (B) Tissue stained with a positive control probe, which binds a highly expressed canine mRNA sequence, showed widespread staining. (C) Tissue was stained with a probe that specifically binds FVIII mRNA. Red dots indicate the presence of either (B) positive control mRNA or (C) pLP-hF8-X10 mRNA in canine liver tissue collected upon necropsy at 60 days after surgery. Liver was cut into 1-cm squares and frozen in optimal cutting medium, then sectioned at 7 microns and subjected to the RNAscope 2.5 HD – Red Assay. Sections were also stained with hematoxylin to show tissue morphology. Each red dot indicates the presence of 1 copy of pHP-hF8-X10 mRNA in experimental canine tissue. All sections shown are representative selections from the RLL of FLR004, section D6.