CD34 and neoplasm: In the mouse Hep3B cell-xenograft model, an immunohistochemical study of CD34 revealed that the number of CD34-positive cells in Hep3B tumors treated with mIFN-β was decreased when compared to that seen in the Hep3B tumors treated with hIFN-β, indicating that tumor vascular formation was more severely suppressed with mIFN-β treatment than with hIFN-β treatment (Fig. 7).