5'-nucleotidase, cytosolic II genotype, and clinical outcome in patients with acute myeloid leukemia with intermediate-risk cytogenetics.

Acute myeloid leukemia (AML) is a complex disease, and its treatment needs to be adjusted to the risk, which is conferred by cytogenetics and molecular markers. Cytarabine is the main drug to treat AML, and it has been suggested that the genotype of cytarabine metabolizing enzymes may have a prognostic relevance in AML. Here we report the association between the 5'-nucleotidase, cytosolic II (NT5C2) rs10883841, cytidine deaminase (CDA) rs2072671 and rs532545 genotypes and the clinical outcome of 477 intermediate-risk cytogenetic AML patients receiving cytarabine-based chemotherapy. Patients younger than 50 years old with the NT5C2 rs10883841 AA genotype had lower overall survival (OS) (p: .003; HR 2.16, 95% CI 1.29-3.61) and lower disease-free survival (DFS) (p: .002; HR 2.45, 95% CI 1.41-4.27), associated to a higher relapse incidence (p: .010; HR 2.23, 95% CI 1.21-4.12). Interestingly, subgroup analysis showed that the negative effect of the NT5C2 rs10883841 AA genotype was detected in all subgroups except in patients with nucleophosmin mutation without high ratio FLT-3 internal tandem duplication. CDA polymorphisms were associated with the complete remission rate after induction chemotherapy, without influencing OS. Further studies are warranted to determine whether this pharmacogenomic approach may be helpful to individualize AML treatment.

UGT1A1 genotype influences clinical outcome in patients with intermediate-risk acute myeloid leukemia treated with cytarabine-based chemotherapy.

The treatment of acute myeloid leukemia (AML) is adjusted according to cytogenetic risk factors and molecular markers. Cytarabine remains the main drug to treat AML, and several studies have explored the prognostic relevance of the genotype of cytarabine metabolizing enzymes in AML. Glucuronidation has been identified to be relevant in the cytarabine clearance, but there are still few data concerning the clinical impact of genetic polymorphisms known to condition the activity of UDP-glucuronosyl transferases in AML patients. Here we report the association between the UGT1A1 rs8175347 genotype and the clinical outcome of 455 intermediate-risk cytogenetic AML patients receiving cytarabine-based chemotherapy. Patients with the UGT1A1*28 homozygous variant (associated to a lower UGT1A1 activity) had a lower overall survival (OS) (25.8% vs. 45.5%; p: 0.004). Multivariate analysis confirmed this association (p: 0.008; HR: 1.79; 95% CI: 1.16-2.76). Subgroup analysis showed the negative effect of the UGT1A1*28 homozygous genotype on OS in women (14.8% vs. 52.7%; p: 0.001) but not in men. This lower OS was associated with longer neutropenia after consolidation chemotherapy and with higher mortality without previous relapse, suggesting an association between a low glucuronidation activity and mortal toxic events.

Kinetics of the CTLA-4 isoforms expression after T-lymphocyte activation and role of the promoter polymorphisms on CTLA-4 gene transcription.

Cytotoxic T lymphocyte antigen 4 (CTLA-4) plays a key inhibitory role during T lymphocyte activation. The CTLA4 gene is translated into two proteic isoforms: a full-length protein (flCTLA-4) and a soluble counterpart. We explored the expression of both isoforms on healthy subjects. Whereas in non-stimulated cells the flCTLA-4 isoform is predominant, after stimulation the expression of the soluble form rapidly increases, reaching its maximum 24h after and falling again to the basal levels 72 h after stimulation. In contrast, the flCTLA-4 mRNA levels increase is slower, reaching the maximum level 72 h after stimulation. The presence of the T allele in the promoter positions -1722 and -318 is associated with an increased transcriptional activity and this effect seems to be synergic. We conclude that the kinetics of CTLA-4 isoform expression are sequential, and that the promoter polymorphisms -1722(C/T) and -318(C/T) are involved in the control of the CTLA4 transcription.