The importance of p16INK4a repression in angiosarcoma was also evident from canine studies that showed sustained expression of p16INK4a in 100% of benign hemangiomas (a total of ten were examined), and p16INK4a suppression in 82% (32 out of 39) angiosarcomas (Yonemaru et al., 2007). This evidence concerns the gene CDKN2A and hemangioma.