Concentration of lipocalin region of collagen XXVII alpha 1 in the serum of dogs with hemangiosarcoma

Background: Hemangiosarcoma (HSA) is a common malignancy of dogs with characteristic early, aggressive metastasis. Diagnosis of HSA is challenging because of lack of sensitive and specific diagnostic tests. Hypothesis: Specific proteins that are increased in serum of dogs with HSA might represent useful biomarkers of the disease. Animals: Thirty-four dogs with HSA and 42 healthy dogs from the Ontario Veterinary College Teaching Hospital. Methods: This case-control study compared serum proteins in dogs with HSA and healthy dogs. Proteins were separated by 2-dimensional difference gel electrophoresis and identified by liquid chromatography and tandem mass spectrometry. Results: Western blot analysis showed that serum collagen XXVII peptide concentration in serum of dogs with large metastatic HSA burdens (1,488, 231–3,754 DU; median, minimum-maximum); was, on average, 9.5-fold higher than in healthy dogs (156; 46–2,101 DU). While concentrations for dogs with osteosarcomas (678; 124–3,251 DU), lymphomas (423; 92–2,777 DU), carcinomas (1,022; 177–3,448 DU), and inflammatory disease were also increased, values were consistently lower than those for HSA. Receiver operating characteristic curves revealed an estimated area under the curve of 83% for HSA cases whereas areas for other neoplastic and nonneoplastic diseases were nondiscriminatory. Serum collagen XXVII peptide concentration before splenectomy (1,350; 1,156–1,929 DU) was reduced after tumor removal (529; 452–562 DU) and chemotherapy but increased in 2 dogs with tumor recurrence (511–945 DU; 493–650 DU). Conclusions and Clinical Importance: Collagen XXVII peptide might be useful for diagnosis and monitoring of advanced HSA.