Both his relapsed cf-tDNA sample and recurrent tumor tissue were detected to have newly emerging CDKN2A:p.L16Pfs*9 and PDGFRA:p.V536E mutations compared to the initial tissue (Figure 2B), indicating that the relapsed tumor had evolved more malignant branches featured with CDKN2A loss (20). This evidence concerns the gene PDGFRA and neoplasm.