ABSTRACT
Objective According to the requirements of the College of American Pathologists (CAP),to validate the laboratory developed test-JAK2 V617F mutation.Methods This is a clinical laboratory diagnosis study.Fifty-seven peripheral blood and bone marrow samples were collected from the BCR/ABL-negative myeloproliferative neoplasms (MPN) patients in Huashan Hospital from Apr 2010 to Dec 2010.JAK2 V617F mutation was detected by fluorescence PCR combined with melting curve analysis.The accuracy,precision,analytical sensitivity,and anti-interference ability of the assay were validated.The Kappa test was used to evaluate accuracy.Coincidence rate was used to evaluate the repeatability.Paired t test was used to evaluate analytical sensitivity.Results There was a close agreement between the reference method(sequencing) and the test method (fluorescence melting curve analysis) (Kappa =0.89).The coincidence rate was 100％.The results of the assay was not affected by lipoprotein (＜ 24 mmol/L) or bilirubin (＜450 μmol/L).The detection limit of the assay was 5％.Conclusion JAK2 V617F mutation assay by fluorescence PCR combined with melting curve analysis could be applied to the clinical laboratory.
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Objective To investigate a new single nucleotid polymorphism (SNP) intron5(+4668C/T) in SLC22A12 in primary gout patients and the association between clinical characteristics and genotypes. Methods One hundred and one primary gout patients and 186 healthy subjects were recruited into this study. Blood pressure, body mass index (BMI) was recorded. Serum uric acid, glucose, lipid and creatinine were detected. DNA was extracted from peripheral blood to amplify the fragment located in intron 5. The genotypes of SLC22A12 can be detected with high-resolution melting (HRM) assay, followed by sequencing analysis. Chi-square test was used for statistical analysis. Results ① A new SNP in intron 5 of SLC22A12 was identi-fied successfully by HRM, which was defined as intron 5 (+4668C/T). CC, CT and TT genotypes were unam-biguously distinguished with HRM technology, which was fully concordant with sequencing. ②The genotypes of CC, CT and TT in male and female groups were 28.1%, 33.7%, 38.2% and 20.0%, 47.1%, 32.9%, respectively.③ However, no significant differences of genotype distribution were found concerning BMI, blood pressure, creatinine, total cholesterol and triglyceride in both male group and female group. But the serum uric acid levels in the CC genotype were significantly higher than those with the CT+TT genotypes. ④ The genotype frequencies of CC and CT+TT in high uric acid group were remarkably different from those in low uric acid group (21.2%, 78.8%,; 35.0%, 65.0%; P<0.05). Conclusion A new SNP has been successfully discovered with HRM technology with simplicity, rapidity and accuracy. T allele of intron 5 (+4668C/T) may be a genetic protective factor for hyperuricemia among Chinese population.
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Objective To establish quantitative method for detection of methylation level of DLC-1 promoter with HRM technology to analyze its association with pathological parameters in prostate cancer.Methods 89 prostate cancer tissue samples and 10 matched normal tissue samples were enrolled into this study.Prostate cancer cells were obtained by LCM.DNA was extracted and modified for methylation determination.CpGenome Universal Methylated DNA was chosen as 100% methylation sample.Then the calibrators representative of 100%,80%,50%,30%,10% and 0% methylation levels were prepared with dilution in a DNA sample of peripheral blood from healthy subjects(100% non-methylation).The DLC-1 methylation levels in prostate cancer tissue samples were detected with HRM.The associations of methylated level with age of patients,PSA value,TNM stage were investigated respectively.ResultsThe melting curves representing 100%,80%,50%,30%,10% and 0% methylation levels were aligned from right to left.The methylation levels of 10 adjacent normal samples and 35 prostate cancer samples were overlapped with 0% methylated calibrator.The methylation levels of 5 cancer samples ranged between 0% and 30%.The methylation levels of 29 cancer samples ranged between 31% and 80%.The methylation levels of 20 cancer samples ranged between 81% and 100%.HRM could be used to reliably detect the as low as 10% methylation for each assay,whereas methylation specific PCR(MSP) could be used to detect 30% methylation level.No significant association between methylation level and patients' age(X~2=3.29,P=0.19),PSA level(X~2=2.04,P=0.36) was found.However,DLC-1 methylation was higher in the prostate cancer tissues with advanced TNM stage(X~2=9.04,P=.01).Conclusions The quantitative method for DLC-1 methylation with HRM is successfully established.It is convenient with good reproducibility and high sensitivity.DLC-1 methylation could be used as the molecular marker for estimation of malignancy in prostate cancer.
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Objective To establish real-time PCR method for the detection of JAK2 V617F mutation and evaluate its clinical significance in patients with myeloprollferative disorders and leukemia.Methods 71 chronic myelocytic leukemia(CML) patients, 22 essential thrombocythemia (ET) patients, 11 primary myelofibrosis (PMF) patients, 9 polycythemia vera (PV) patients and 7 cosinophilia patients were enrolled in this study. JAK2 V617F mutation was determined by real-time PCR and amplification refractory mutation system (ARMS), followed by sequencing. Human erythroleukemia cell (HEL cell)DNA was used as homozygous control of JAK2 V617F mutation. The detection limit for either real-time PCR or ARMS was evaluated. Results Real-time PCR assay showed that there was a melting temperature(Tin) peak at (75.0±0.2)℃ for wild type samples and a Tm peak at (76.6±0.2)℃ for mutation type samples. JAK2 V617F mutation was detected in 8(88.9%) patients with PV, 12(54.5%) patients with ET and 7(63.6%) patients with PMF respectively. But there was only one positive case in 71 CML patient (1.4%). The results showed complete concordance with ARMS results and confirmed by sequencing. The mutation could be detected in 102 HEL cells per 106 white blood cells by real-time PCR, whereas the mutation can be assessed in 104 HEL cells per 106 white blood cells by ARMS. Thus, the sensitivity of real-time PCR was 100-fold higher than ARMS. Conclusions The real-time PCR method is successfully established for detection of JAK2 V617F mutation. This method is more sensitive, convenient than ARMS, and suitable for clinical application. There is high frequency of JAK2 V617F mutation in myeloproliferative disorders and it could be used as the diagnostic marker for myeloproliferative disorders.