<i>GSTP1</i> rs1695 showed the smallest p value for hematotoxicity association, and the <sup>105</sup>Ile wild type allele had a significantly higher risk of severe hematotoxicity (neutropenia G4, thrombocytopenia ≥ G3 and anemia ≥ G3) than the <sup>105</sup>Val allele (p=0.00034, odds ratio=5.71 (95% confidence interval:1.77-18.44)).
On evaluating higher order gene-gene interaction models by MDR analysis, GSTM1 and GSTP1 Ile105Val; GSTM1 and GSTT1; and GSTT1 and GSTP1 Ile105Val showed significant association with treatment response, grade 2-4 anemia, and dose delay/reduction due to neutropenia (P=0.046, P=0.027, P=0.026), respectively.