Expression of angiostatic factors in colorectal cancer

Angiogenesis plays an important role in growth and proliferation of cancer. Various angiogenic and angiostatic factors regulate angiogenesis. We exami ned expression of genes encoding various angiostatic factors: thrombospondi n 1 (TSP1), thrombospondin 2 (TSP2), brain-specific angiogenesis inhibitor 1 (BAI1) and angiopoietin 2 (AGP2) in 62 colorectal cancers and 40 samples of extraneoplastic colon mucosa. The expression of the angiostatic factors TSP2 and AGP2 were significantly increased in the cancerous mucosa as compa red to these in extraneoplastic mucosa (chi(2) test; p<0.0001, and Fisher's exact test; p<0.0001), while the increase in TSP1 expression was not signi ficant. BAIL expression was slightly decreased in the cancer tissue. These results suggested that specific types of angiostatic factors might have pro tective roles against cancer cell proliferation via dormancy due to hyponut rition caused by decreased vascularity.