LAUSR

BACKGROUND Serum-based parameters are considered non-invasive biomarkers for cancer detection. In human studies, insulin-like growth factor-I and II (IGF-I and IGF-II) and insulin-like growth factor binding protein-3 (IGFBP-3) are useful as diagnostic or prognostic markers and potential therapeutic targets. OBJECTIVES This study examined the diagnostic utility of circulating IGF-I, IGF-II, and IGFBP-3 levels in healthy dogs and dogs with tumors. METHODS The serum concentrations of these biomarkers in 86 dogs with tumors were compared with those in 30 healthy dogs using an enzyme-linked immunosorbent assay (ELISA). RESULTS The ELISA results showed no difference between healthy dogs and dogs with tumors in the serum IGF-II concentrations. On the other hand, there was a significant difference in the circulating IGF-I and IGFBP-3 levels between healthy dogs and dogs with tumors. The concentrations of serum IGF-I (median [interquartile range], 103.4 [59.5-175] ng/mL) in dogs with epithelial tumors were higher than those (58.4 ng/mL [43.5-79.9]) in healthy dogs. Thus, the concentrations of serum IGFBP-3 (43.4 ng/mL [33.2-57.2]) in dogs with malignant mesenchymal tumors were lower than those (60.8 ng/mL [47.6-70.5]) in healthy dogs. CONCLUSIONS The serum IGF-I and IGFBP-3 levels can be used as diagnostic biomarkers in dogs with tumors.