Fig. 2

Detection of NF-κB p65 in feline injection site sarcomas (FISSs) by immunohistochemistry assay (IHC). Unequivocal brown nuclear NF-κB staining (arrows) in at least 5% of tumor cells were designated as positivity. In NF-κB p65-positive FISS cases, the expression of NF-κB p65 was consistent without distinct variation. a NF-κB p65-positive, grade I FISS. b NF-κB p65-positive, grade II FISS. c NF-κB p65-positive, grade III FISS. d Lymphoid aggregates peripheral to the neoplasm expressed nuclear NF-κB p65 subunits. e NF-κB p65-negative, grade III FISS. Nuclear signals (arrowhead) presented in less than 5% of neoplastic cells were designated as negativity. f Negative control