Tumour endothelial marker 8 (TEM-8) in human colon cancer and its association with tumour progression.
OBJECTIVE
Tumour endothelial marker-8 (TEM-8) is endothelial cell surface marker that may be specific to tumour endothelial cells. This study examined the role of TEM-8 in human colon cancer and its correlation with tumour prognosis.


METHODS
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 lines. 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 endothelial 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). Malignant cells in tumour tissues were found to be stained strongly positive for TEM-8 compared with the epithelial 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).


CONCLUSIONS
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.
Rmali
K A
KA
Metastasis and Angiogenesis Research Group, University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK. rmalika@cf.ac.uk
Watkins
G
G
Harrison
G
G
Parr
C
C
Puntis
M C A
MC
Jiang
W G
WG
D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000378:metabolism*; D018450:Disease Progression; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009363:Neoplasm Proteins; D009389:Neovascularization, Pathologic / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C473287:ANTXR1 protein, human; D014408:Biomarkers, Tumor; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009363:Neoplasm Proteins; D012334:RNA, Neoplasm; D011956:Receptors, Cell Surface