In the present study, we detected significantly lower PTEN expression but higher PIK3CA, pMAPK, and TP53 expression in tumor tissues of scalp and face angiosarcoma than in benign hemangioma, and these differences in the expression of cancer-related proteins were correlated with the degree of tumor differentiation and coincided with reduced apoptosis in angiosarcoma compared to hemangioma. This evidence concerns the gene PIK3CA and cancer.