FAS and myeloid leukemia: Based on observations in myeloid leukemia, IRF-8 may regulate Fas responsiveness by acting as a transcriptional activator of pro-apoptotic genes, such as caspases, and/or a transcriptional repressor of anti-apoptotic genes, such as PTPN13 (FAP-1) or members of the Bcl-2 family [19], .