In the majority of glioma cell lines tested (7 out of 9), the copy numbers of the mutant allele approached the total number of all Pdgfra alleles (note that mutant specific primers can not detect the wild-type Pdgfra allele), indicating a preferential amplification of the PDGFRα J/K mutant allele (Fig. 3a). The gene discussed is PDGFRA; the disease is glioma.