Quantification of VEGF-C expression in canine mammary tumours

Background Tumours release angiogenic factors such as vascular endothelium growth factor (VEGF), which induces growth of a capillary network around the tumour. Elevated concentrations of VEGF have been reported in human mammary gland tumours. Methods To evaluate the expression of VEGF-C mRNA in canine mammary tissue, 38 mammary gland tumours (including 15 benign and 23 malignant mammary tumours), and 4 normal mammary glands were investigated by real-time reverse transcriptase quantitative polymerase chain reaction. Results VEGF-C expression in the malignant mammary tumours was much higher than in the benign mammary tumours or normal mammary-tissue (P < 0.001). The expression of VEGF-C in tumours with lymph node metastasis was much higher than in those without (P < 0.01). Conclusion The level of expression of VEGF-C did not correlate with tumour size or the patient's age, but was significantly higher in malignant mammary tumours and related to lymph node metastasis, making it a candidate marker for predicting metastasis of canine mammary cancer.