Big endothelin-1 as a tumour marker for canine haemangiosarcoma

• Serum big endothelin-1 (ET-1) concentrations were determined by ELISA in normal dogs and dogs with splenic lesions.
• Serum big ET-1 concentrations were increased in dogs with splenic haemangiosarcoma (HSA).
• Serum big ET-1 had high sensitivity and specificity values for diagnosis of HSA.
• ETA, Hif1-α and PPET-1 mRNA are up-regulated in HSA.
• The ETA axis may play an important role in the overproduction of PPET1.

Haemangiosarcoma (HSA) is an important malignant neoplasm of dogs that originates from vascular endothelial cells. This study explored the suitability of using serum big endothelin-1 (ET-1) as a tumour marker for canine spontaneous HSA. Serum big ET-1 was measured in dogs with splenic HSA (n = 14), splenic malignant tumours other than HSA (n = 10), benign splenic lesions (n = 11) and normal healthy dogs (n = 17) by ELISA. Serum big ET-1 levels in dogs with HSA were significantly (P < 0.01) higher than in other dogs. High sensitivity (100%, 95% confidence interval 86–100%) and specificity (95%, 95% confidence interval 86–95%) for HSA diagnosis were obtained using a cut-off of 17 pg/mL according to receiver operating characteristic (ROC) curves (area under ROC curve 0.93). PPET1, ETA, VEGF and Hif1-α mRNA expression, measured by real-time PCR, were elevated in HSA compared with normal tissues. These findings suggest that elevated serum big ET-1 could be used as a diagnostic marker for canine HSA.