NOS2 and acute promyelocytic leukemia: A relationship of the NOS3 (27-bp, intron 4) polymorphism and osteomyelitis27 and of the NOS3(Glu298Asp) polymorphism and hip osteoporotic fractures28 was previously reported emphasizing the key role of NO in bone metabolism.Thus, the mechanism underneath the association of this NOS2 (exon 22) polymorphism and APL remain elusive.