We found that the PDGFRA signaling pathway in sarcoma cells, which have CDK4 amplification and PDGFRA expression, was disarranged by CDK4 activation, with decreased effects of drugs targeting PDGFRA. Finally, the molecular characteristics of the CS group were defined as a PDGFRA putative target group. The gene discussed is CDK4; the disease is Cowden syndrome 1.