Characteristics of C-reactive Protein (CRP), a1-acid Glycoprotein (AAG) and Serum Amyloid A (SAA) in Dogs and Cats with Malignant Cancer

The changes in serum concentrations of C-reactive protein (CRP), a1-acid glycoprotein (AAG,) and serum amyloid A (SAA), in dogs and cats with cancer were investigated. On initial examination, serum concentrations of CRP and AAG showed elevated levels in dogs with cancer. On the other hand, serum concentrations of SAA in cats with cancer were below the detection limit, and AAG was only elevated in one cat tested. CRP and AAG increased after operation to remove cancer in dogs, while SAA and AAG increased after operation in cats. However, CRP and AAG again increased at several months after operation in dogs, and this was thought to be due to metastasis, incomplete removal of cancer or presence of infection. However, this phenomenon was not observed in cats. Thus, CRP and AAG may be useful as adjunct markers of malignant cancer in dogs, but not in cats. Tumor antigens in dogs and cats could not be measured using reagents for humans.