ABSTRACT
Objective To investigate the association between single nucleotide polymorphisms (SNPs) of ATP-binding cassette B1 (ABCB1),ATP-binding cassette C2 (ABCC2) and solute carrier organic anion transporter 1B1 (SLCO1 B1) genes with high dose methotrexate (HDMTX)-induced toxicity in children with acute lymphoblastic leukemia (ALL).Methods This study was designed as a casecontrol.From September of 2005 to December of 2011,the blood samples were randomly collected from 142ALL patients from Nanjing Children's Hospital,Enzyme-multiplied immunoassay technique (EMIT) was used to measure the plasma concentration of MTX,Seven SNPs in ABCB1 (rs1045642,rs2032582,rs1128503),ABCC2 (rs717620,rs2273697) and SLCO1 B1 (rs4149081,rs11045879) genes were detected by polymerase chain reaction-ligase detection reaction (PCR-LDR).Results A significantly increased risk of MTX-induced toxicity was observed in patients with MTX elimination delay (OR ＝ 2.828,95％ CI:1.217-6.571,P ＜ 0.05).Two SNPs in SLCO1B1,rs4149081 and rs11045879 were linkage disequilibrium (LD) with each other (R2 =0.979,P ＜ 0.05).Multivariate analysis revealed that individuals with SLCO1B1 rs4149081 AA genotype or SLCO1B1 rs11045879 CC genotype showed increased incidence of MTX elimination delay (OR =4.41,95％ CI:1.537-12.654,P =0.042),and the two genotypes were also associated with significantly increased risk of MTX-induced toxicity (OR =4.118,95％ CI:1.135-14.944,P =0.022).No association of MTX elimination delay or MTX-induced toxicity with the other SNPs analyzed was found.Conclusions SLCO1B1 rs4149081 AA or SLCO1B1 rs11045879 CC genotypes might be a risk factor for the susceptibility to MTX-induced toxicity in children with ALL.
ABSTRACT
Objective To investigate the influences of the functional polymorphisms of cytochrome P450 isozymes 2A6 (CYP2A6),2B6 (CYP2B6),2C9 (CYP2C9),and 2C19 (CYP2C19) on plasma concentration of sodium valproate.Methods A total of 131 Chinese children with epilepsy receiving sodium valproate after a period of more than 5 half-time were recruited.The genotypes of CYP2A6 were detected by multiplex polymerase chain reaction (PCR),and the genotypes of CYP2B6,CYP2C9,and CYP2C19 were detected by PCR-ligase detection reaction.Enzyme-multiplied immunoassay technique was used to measure the plasma concentration of sodium valproate.The association between the polymorphisms and the plasma concentration of sodium valproate were analyzed by one-way ANOVA or Student' s t-test.Results Patients were divided into 4 groups according to the genotyping results of CYP2C9 and CYP2C19 (G1:extensive metabolizers in both CYP2C9 and CYP2C19; G2:CYP2C19 intermediate metabolizers; G3:CYP2C19 poor metabolizers; G4:CYP2C9 poor metabolizers),the mean normalized steady-state sodium valproate concentrations were significantly higher in G3 (3.70 ± 0.95) and G4 (4.35 ± 1.48) patients when compared to those in G 1 (2.57 ± 1.30,t =3.056,4.490,both P ＜ 0.01) and G2 (2.76 ± 1.19,t =2.827,4.462,both P ＜ 0.01) patients.The daily doses (mg/d) of sodium valproate received by G3 (19.46 ± 5.20) and G4 (19.30 ±7.67) patients were significantly lower than that of G1 patients(24.10 ±6.97,t =2.359,2.297,both P ＜ 0.05).There were no differences in daily doses or normalized steady-state concentrations of sodium valproate among the CYP2A6* 4 or CYP2B6* 6 genotypic groups.Conclusions The CYP2C9 and CYP2C19 polymorphisms have dramatic effects on the plasma concentration of sodium valproate.The daily doses of sodium valproate in G3 and G4 patients should be lower than usual.