Levels of expression of endothelial markers specific to tumour-associated endothelial cells and their correlation with prognosis in patients with breast cancer

Abstract

Tumour endothelial markers (TEMs) are a newly discovered family of endothelial markers associated with tumour specific angiogenesis. This study sought to examine the levels of expression for TEMs in human breast cancer. Breast cancer tissues (n = 120) together with normal background tissues (n = 33) were obtained after surgery. RNA was extracted from frozen sections for gene amplification. The expression of TEMs was assessed using RT-PCR and the quantity of their transcripts was determined using real-time-quantitative PCR (Q-RT-PCR). TEM-7R (P = 0.05) and TEM-8 (P < 0.01) were significantly raised in breast cancer tissues compared with the levels detected in normal background tissues. After a median follow-up of 72.2 months it was found that patients who had recurrent disease and/or who had died from breast cancer had a significantly (P < 0.05) elevated level of TEM-1 compared to those patients who were disease free. In addition, elevated levels of TEM-4, TEM-5, TEM-6, TEM-7 and TEM-7R were also raised in breast cancer tissues. Patients who had developed nodal involvement exhibited significantly (P < 0.05) high levels of TEM-1 and TEM-7R compared to patients who were node negative. Furthermore, the levels of TEMs did not correlate with tumour or histological grade. We conclude that elevated levels of TEM-1, TEM-7R and TEM-8 (but not TEM-2, 4, 5, 6 and 7) are associated with either nodal involvement, and/or disease progression, and may therefore, have a prognostic value in breast cancer.