In this study, the role of the polymorphism at codon 72 of tumor protein p53 gene (TP53) was investigated regarding the response to treatment with imatinib in chronic myeloid leukemia (CML).

A total of 85 patients with CML were treated according to the Brazilian National Cancer Institute (INCA) guidelines and at the end of the 18th month a blood sample were collected for genotyping. Genomic DNA was extracted and TP53 codon 72 genotyping was performed by allele-specific polymerase chain reaction (AS-PCR), which detects argine or proline alleles.

Of the 85 CML samples, 27 samples were homozygous for arginine (Arg/Arg), 12 homozygous for proline (Pro/Pro) and 46 samples heterozygous (Arg/Pro). TP53 codon 72 polymorphism was in Hardy–Weinberg equilibrium (χ²=1.17, P=0.37). We did not find significant association between codon 72 polymorphism and age at diagnosis and sex (P=0.76 and P=0.33, respectively). High Sokal score are significantly associated with Arg/Arg genotype carriers (Odds ratio, OR=4.09; 95% confidence interval, CI 1.01=15.89; P=0.036). The arginine allele in homozygosis also have an increased risk of failure response to imatinib when compared with both, the heterozygous (Arg/Pro) and proline homozygous patients (P=0.021; OR=2.99, 95% CI=1.16–7.67). Additionally, interaction analysis with age at diagnosis revealed that among patients over 40-yr old, Arg/Arg genotype was significantly associated with non-responder patients (P=0.007; OR=5.13, 95% CI=1.5–17.55).

The findings suggest that in CML patients, TP53 codon 72 polymorphism may contribute to a high Sokal score and failure to imatinib treatment.