Tumour endothelial marker 8 (TEM-8) in human colon cancer and its association with tumour progression

Background and aims. Tumour endothelial. marker-8 (TEM-8) is endothelial. cell surface marker that maybe specific to tumour endothelial cells. This study examined the role of TEM-8 in human colon cancer and its correlation with tumour prognosis. Methodology. Specimens of colorectal. tissue (normal and cancer) were stained immunohistochemically with an anti-TEM-8 antibody, newly developed in our laboratory, and with anti-vonWillebrand Factor antibody. RNA was extracted from frozen sections for gene amplification. The anti-TEM-8 antibody specificity tested by using slot blotting with irrelevant antibody, and western blotting with different cell tines. The expression of TEM-8 was assessed using RT-PCR, and the level of TEM-8 was quantified using real-time-quantitative PCR (Q-RT-PCR). Results. TEM-8 staining was primarily seen in enclothelial cells. TEM-8 identified more micro-vessels in colon tumour tissue, than-in normal colon tissues, (p=0.002). Whereas, fewer vessels were stained positive for TEM-8 in normal. tissues stained positive for vonWillebrand Factor (factor-8), (p=0.008). Matignant cells in tumour tissues were found to be stained strongly positive for TEM-8 compared with the epithetial cells in normal colon tissues. The level of TEM-8 expression was significantly higher in the tumour tissues compared to the normal colon mucosa (p=0.001). TEM-8 mRNA expression was also found to be more elevated in patients with advanced tumour, Dukes C (Dukes A vs. Dukes C, p=0.01). Conclusion. TEM-8 is a marker that identifies tumour associated micro-vessels in colon cancer. The levels of expression of TEM-8 in invasive colon cancer are linked to disease progression. This suggests that TEM-8 has significant prognostic and therapeutic values in colon cancer. (C) 2004 Elsevier Ltd. Alt rights reserved.