Analysis of DNA methylation levels at the TSS in specific tumor-related genes revealed a decreased promoter methylation level for POU5F1 in seminomas (approximately 35% reduction in DNA methylation) as compared to both d0-PTCs and LT-PTCs, while we did not detect significant differential methylation in SCGB3A1, PRSS21 or HIC1 (Fig 3B). This evidence concerns the gene PRSS21 and seminoma.