The results of the present study with respect to CASP9 -1263G>A polymorphism had revealed that CASP9 -1263AG/GG genotypes and G allele might confer risk for the development of CML which was in accordance with case-control studies on breast cancer by Theodoropoulos et al. (2012) who reported individuals with CASP9 -1263AG or CASP9 -1263GG genotypes were at higher risk for breast cancer. This evidence concerns the gene CASP9 and breast cancer.