Objective To evaluate the sensitivity, repeatability and accuracy of microarray digital PCR system in detecting JAK2 V617F mutation, which was closely related to myeloproliferative neoplasms (MPN).Methods All of the 31 MPN patients with JAK2 V617F mutation, including 18 cases of polycythemia vera(PVs),11 primary thrombocythemias (ETs) and 2 primary myelofibrosis (PMFs), were collected from Huashan Hospital, Fudan University during 2014 -2015, while 10 normal controls and 6 cases with abnormal increased hemoglobin were involved.Human erythroleukemia cell line ( HEL ) and colorectal cancer cell SW480 were used as the mutant and the wild type control, respectively.The sensitivity of microarray digital PCR were verified by detecting the gradient diluted mutation standard harboring 30%, 10%, 1%, 0.1%and 0.01%mutant allele burden, respectively .Repeatability was evaluated by detecting 1%and 10% mutated samples for 5 times, respectively.MGB probe real time PCR was selected as the reference method to verify the accuracy of the digital PCR.Results With digital PCR, the accurate quantitation of JAK2 V617F mutation was achieved down to 0.1%, which is approximate to 0.16 copies per microliter.The results obtained from the two kinds of technique showed a high correlation by linear regression analysis (R2 =0.998 3).The results of repeated samples showed CVs as 17.18% for 1%mutant allele burden and 7.50%for 10%.Among all cases, the 31 patients known mutated were detected as positive and 10 controls as negative by both digital PCR and Real time PCR.In another 6 cases, 2 were found JAK2 V617F mutation of low allele burdens of 0.37% and 0.18% by digital PCR but detected as negative by real time PCR.Conclusions Microarray digital PCR offers a higher sensitivity and better repeatability than real time PCR which could help detect rare JAK2 V617F mutations in MPNs accurately.

Objective To investigate the diagnostic efficacy and clinical value of GNB4 and Riplet gene methylation alone and in combination in the diagnosis of primary liver cancer.Methods A total of 313 patients were selected,including 78 patients with primary liver cancer,41 patients with other digestive system tumors,17 patients with non-digestive system tumors,20 patients with postoperative liver cancer,and 157 patients with benign liver disea-ses.The levels of GNB4 and Riplet gene methylation in plasma were detected using quantitative methylation-specific PCR(qMSP).Serum alpha-fetoprotein(AFP)levels were measured by direct chemiluminescence.Results The sensitivity and specificity of AFP in diagnosis were 51.3％and 94.3％,respectively;the sensitivity and specificity of GNB4 gene methylation in diagnosis were 83.3％and 99.4％,respectively;the sensitivity and specificity of Riplet gene methylation in diagnosis were 73.1％and 99.4％,respectively.The sensitivity and specificity of GNB4 and Riplet gene methylation combined diagnosis were 92.3％and 98.7％,respectively;the sensitivity and specificity of AFP,GNB4 and Riplet gene methylation combined diagnosis were 92.3％and 98.7％,respectively;the sensitivity and specificity of combined diagnosis including age and gender were 93.6％and 97.5％,respective-ly.Conclusion The sensitivity and specificity of AFP in the diagnosis of primary liver cancer are limited,while the methylation levels of GNB4 and Riplet genes are higher,and the sensitivity and specificity of their combined de-tection are higher than those of AFP.The sensitivity and specificity of AFP,GNB4 and Riplet gene methylation combined diagnosis are significantly higher than those of AFP,GNB4 and Riplet gene methylation alone.

Objective: To investigate the value of combined stool syndecan-2 (SDC2) and tissue factor pathway inhibitor 2 ( TFPI2) gene methylation testing in the early screening of colorectal cancer． Methods : 106 patients with colorectal cancer (colorectal cancer group) ，75 patients with advanced adenoma ( advanced adenoma group) and 35 patients with non-advanced adenoma (non-advanced adenoma group) were selected as study subjects，and 153 patients with other gastrointestinal disorders and 182 patients with negative colonoscopy results during the same period were selected as the control group．The quantitative methylation-specific PCR(qMSP) method was used to detect SDC2 and TFPI2 gene methylation in the stool specimens of all subjects．The sensitivity and specificity of the combined SDC2 and TFPI2 gene methylation assay for the detection of colorectal cancer and adenoma were evaluated using colonoscopy and pathology results as the gold standard. Results : Among 106 patients with colorectal cancer， the sensitivity of combined methylation test was 93. 4% ; among 75 patients with advanced adenoma，the sensitivity of combined methylation test was 62. 7% ; among 35 patients with non-advanced adenoma，the sensitivity of combined methylation test was 34. 3% ; the specificity of the combined SDC2 and TFPI2 gene methylation test for colorectal cancer and adenoma screening was 94. 6%． Conclusion The combined SDC2 and TFPI2 gene methylation test has high sensitivity for colorectal cancer and its early lesions，and it also maintains high specificity.