Angiogenesis in colon hyperplastic polyp.

Despite the significance of tumor angiogenesis and the extensive knowledge on the molecular basis of blood vessel formation in carcinoma of colorectum, no data exist in hyperplastic polyp. This prompted us to examine angiogenesis in hyperplastic polyp. Eleven small hyperplastic polyps, 13 large hyperplastic polyps and their adjacent normal mucosas were included in this study. Angiogenesis was assessed by immunohistochemistry using monoclonal antibody against CD34. Angiogenic factor, thymidine phosphorylase was also examined by immunohistochemistry. Intra-tumoral microvessel density (IMD) in large hyperplastic polyp was significantly higher than that in small hyperplastic polyp (P<0.01) and that in normal mucosa (P<0.01). DAD in small hyperplastic polyp was also significantly higher than that in normal mucosa (P<0.01). Expression of dThdPase was almost observed in stromal cells in normal, small and large hyperplastic polyp. In addition, the proportion of the stromal cells expressing dThdPase in large hyperplastic polyp was significantly higher than that in small hyperplastic polyp and normal tissue (P<0.01, respectively). The proportion of the stromal cells expressing dThdPase in small hyperplastic polyp was significantly higher than that in normal tissue (P<0.01). The present study provides that angiogenesis may have an important role(s) in the development of hyperplastic polyp and dThdPase in stromal cells may support angiogenesis in hyperplastic polyp. Anti-angiogenic therapy might be available for suppression of hyperplastic polyp.