Genes involved in polyamine metabolism (ODC1, SRM, SMS, SAT1, PAOX, SMOX) and in the strictly connected pathways [AMD1, arginase (ARG)1/2, MAT2A, MTAP, protein arginine methyltransferase 5 (PRMT5), ornithine aminotransferase (OAT)] are rarely mutated in acute leukemias. The gene discussed is MTAP; the disease is acute leukemia.