CASP9 -293 del (+/−) genotype conferred protection against CML risk as evidenced from observation made with respect to phase of the disease and IM response, while the homozygous CASP9 -293 del (−/−) genotype conferred increased risk for the progression as observed by the elevated frequency of CASP9 -293 del (−/−) genotype in patients diagnosed in blast crisis and in secondary resistance cases. The gene discussed is CASP9; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.