CASP9 and chronic myelogenous leukemia, BCR-ABL1 positive: Although significant association of CASP9 Ex5 +32G>A polymorphism was not observed with the development of CML in the present study, it was observed that the CASP9 Ex5 +32AA genotype had increased the risk to develop secondary resistance which indicated the possibility of interaction between variant genotype and other Bcr/Abl dependent or independent mechanisms.