MAP2K1 and Venous malformation: Although there was no significant difference in the mRNA levels between the section of senile hemangioma and those of other vascular anomalies (Fig. 5), protein expression of MEK1 (Fig. 6a) or cyclin E1 (Fig. 6b) on the proliferated vessels of senile hemangioma was increased compared to normal skin or venous malformation.