For example, it is known that NFAT4 controls the transition of developing thymocytes from the DP CD4+CD8+ immature stage to the CD4+ or CD8+ single positive stage [33], and a tumour suppressor function has also been indicated for NFAT4 in the genesis of T cell lymphomas induced by insertion of the retrovirus SL3-3 [34]. The gene discussed is NFATC3; the disease is T-cell non-Hodgkin lymphoma.