In summary, we detected aberrant PTEN, PIK3CA, pMAPK, and TP53 expression and reduced tumor cell apoptosis in human angiosarcoma of the scalp and face compared with hemangioma, suggesting that the PI3K, MAPK, and TP53 pathways might be associated with angiosarcoma tumorigenesis and the degree of tumor differentiation. The gene discussed is PIK3CA; the disease is neoplasm.