To better clarify these aspects, we analyzed RIZ expression levels and its modulation by estrogens using as a model the normal mouse spermatogonial GC-1 and the seminoma TCam-2 cell lines, because both of them express RIZ proteins (RT-PCR analysis, densitometric analysis and Western blot analysis are reported in Appendix Figure A1). Here, PRDM2 is linked to seminoma.