Clinical application of detection of Warfarin-related gene polymorphisms by DNA sequencing / 中华检验医学杂志

ABSTRACT

Objective To evaluate and analyze the clinical application value of detection of Warfarin-related gene polymorphisms,cytochrome P450 2C9 (CYP2C9) and Vitamin K epoxide reductase complex subunit 1 (VKORC1) polymorphisms.Methods From July of 2011 to July of 2012,the blood samples were randomly collected from 140 lung cancer patients from Department of Oncology in Renmin Hospital of Wuhan University.These lung cancer patients were diagnosed through imaging examination and pathological examination.CYP2C9 and VKORC1 polymorphisms were detected in 70 patients (studied group) but not detected in the other 70 patients (control group) before they used warfarin.According to known gene sequences of CYP2C9 and VKORC1,specific primers were designed to genotype the CYP2C9 *2 and CYP2C9 * 3 alleles as well as the VKORC1-1639G ＞ A polymorphism through PCR amplification and DNA sequencing.Meanwhile,the distribution of these alleles in the studied group was analyzed.The clinical significance of detection of these polymorphisms was evaluated by comparing the proportion of patients within the therapeutic INR (International Normalized Ratio) range between control and genotype-guided dosing groups using Chi square test after 2 and 4 weeks of Warfarin therapy.Results Based on the results of agarose gel electrophoresis of PCR products and DNA sequencing,the primers for CYP2C9 and VKORC1 polymorphisms were indeed specific to these SNPs (CYP2C9 * 1,CYP2C9 * 2 and CYP2C9 * 3 ;VKORC1-1639GG,VKORC1-1639AG and VKORC1-1639AA) and both of the specificity and sensitivity of these primers are 100％,thus contributiug for genotyping these alleles.The distribution of CYP2C9 * 1/* 1 was 100％,CYP2C9 * 1/* 2,CYP2C * 1/* 3,CYP2C9 * 2/* 2,CYP2C9 * 3/* 3 and CYP2C9 * 2/* 3 were 0％.The distribution of VKORC1-1639AG,VKORC1-1639AA and VKORC1-1639 GG were 10％,90％ and 0％ respectively.2 weeks after the treatment of Warfarin,85.7％ patients in the genotype-guided dosing group reached the stable therapeutic INR range,which was significantly higher than that in the control group (48.6％,x2 =21.9,P ＜ 0.01); 4 weeks later,all patients (100％) were inside the stable therapeutic INR range whereas only 65 patients (92.9％) in the control group reached the therapeutic INR range.No haemorrhage or thromboembolic events occurred in both groups.Conclusions CYP2C9 and VKORC1 polymorphisms can be accurately detected by PCR reaction with the designed primers and the subsequent DNA sequencing in patients with lung cancer.This method is validated to be reliable.The genotyping of the Warfarin-related genes detective method can effectively guide Warfarin-dosing.