Strain specific analysis of FAP gene expression in wild-type C57BL/6 mice and B-hFAP mice by RT-PCR. Murine colon cancer MC38 cells (5×10⁵) and melanoma B16-F10 (2×105) were specifically subcutaneously implanted into wild-type C57BL/6 mice, homozygous B-hFAP mice and homozygous B-Fap KO mice. B-CAG-hFAP MC38 cell line which over-expressing human FAP in MC38 cell line was used as a positive control. The mRNA was prepared from kidney tissue of the mice. Mouse Fap mRNA was detectable in kidney tissue of wild-type C57BL/6 mice. Human FAP mRNA was detectable in homozygous B-hFAP mice and B-CAG-hFAP MC38 cell line, but not in wild-type mice. Mouse Fap mRNA and human FAP mRNA were not detectable in homozygous B-Fap KO mice.

Strain specific analysis of FAP expression in wild-type C57BL/6 mice, homozygous B-hFAP mice and B-Fap KO mice by FACS. Murine melanoma B16-F10 (2×10⁵) were specifically subcutaneously implanted into wild-type C57BL/6 mice, homozygous B-hFAP mice and homozygous B-Fap KO mice. Tumor tissue was collected from the three mice, and analyzed by flow cytometry with species-specific anti-hFAP antibody. Human FAP was exclusively detectable in CD45- cells of tumor tissue from homozygous B-hFAP mice but not in that cells from wild-type C57BL/6 mice or B-Fap KO mice.