To exclude underestimation of the incidence of RAS mutations in TGCTs due to the presence of an excess of wild type alleles in the analyzed sample, a PCR technique preferentially amplifying KRAS alleles with a mutation in codon 12 was applied to all SE.
No N-ras mutations were detected in these tumor samples, but two K-ras-2 exon 1 mutations were found in two of the seminoma tumors (stage I and II tumors) using the DGGE technique.
The number of expressed CT genes was significantly higher in seminomas (P = 3.48 × 10<sup>-13</sup> ) which were characterized by frequent mutations in driver genes (KIT, KRAS and NRAS).