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Objectives Transforming anaplastic lymphoma kinase (ALK) gene rearrangements are well known as a unique subset of non-small cell lung cancer (NSCLC) with mutations other than EGFR. Currently, crizotinib is the standard first-line treatment for ALK-positive NSCLC. Materials and methods With advances in detection methods, more and more uncommon ALK fusion partners have been identified. Herein we present a novel SOS1-ALK fusion and the efficacy of crizotinib in an advanced NSCLC patient harboring this type of fusion. Results A 52-year-old Chinese man had left upper lobe primary NSCLC and synchronous multiple lung metastases (cT2N3M1, stage IV). The ultrasound-guided fine-needle aspiration cytology of palpable left supraclavicular lymph nodes and the results of immunohistochemistry staining supported the diagnosis of metastatic lung adenocarcinoma. Using a next-generation sequencing assay (NGS), we showed that the tumor had a SOS1-ALK fusion which the breakpoints was (S2, A20) rather than other actionable mutations. Therefore, the patient received first-line crizotinib and experienced a remarkable tumor response and has tolerated crizotinib well until this writing. Conclusion Considering this rare SOS1-ALK fusion and remarkable response to an ALK-inhibitor, it is important to be aware of the presence of SOS1-ALK fusions in patients with advanced NSCLC to better guide targeted therapy. Precision methods, such as NGS for oncogenic alteration detection, should also be encouraged in clinical practice.

Background BRAF mutation plays a rare but aggressive oncogenic role in non-small cell lung cancer (NSCLC) patients. The controversy of first-line chemotherapy in patients with different BRAF mutations exists. Here, we identified 41 stage IIIB/IV NSCLC patients with BRAF mutation from 3,669 NSCLC patients by next-generation sequencing (NGS) testing of ctDNA in plasma or tumor tissues. Methods Kaplan-Meier survival curves were used to compare the prognostic difference of progression-free survival (PFS) and overall survival (OS) in different classes of BRAF mutations. Multivariate Cox proportional-hazards regression was used to determine the hazard ratio (HR) of different prognostic factors in survival. Results A total of 40 stage IIIB/IV NSCLC patients with BRAF mutation were further divided into four groups according to the updated functional classification of BRAF mutations, 56.1% (23/41) of class 1, 12.2% (5/41) of class 2, 12.2% (5/41) of class 3 and 19.5% (8/41) of others. The median PFS of patients after first-line pemetrexed-based chemotherapy was longer than other regimens of chemotherapy (7.0 vs. 4.0 months, P

The incidence of epidermal growth factor receptor uncommon mutation (EGFRum) is relatively low and patients harboring EGFRum are resistant to the first‐generation tyrosine kinase inhibitors (TKI). However, the mechanism of primary resistance remains unclear. Medical records of 98 patients who had never been treated by TKI and who accepted icotinib treatment were collected and followed. The circulating tumor DNA (ctDNA) were detected and analyzed using the next‐generation sequencing (NGS) platform after progression on icotinib. The potential primary resistance mechanism of icotinib was explored. A total of 21 (21.4%) and 48 (49%) patients developed primary and acquired resistance to icotinib, respectively. The median progression‐free survival (PFS) of primary resistance patients was 1.8 months (0.5‐2.3, 95% CI = 1.50‐2.10). Before treatment, 52.4% (11/21) of patients carried S768I, 23.8% (5/21) L861Q, 14.3% (3/21) G719X and 14.3% (3/21) exon 20‐ins mutations. Approximately 23.8% (5/21) of patients harbored the combined pattern mutations and 76.2% (16/21) of patients harbored the single pattern mutations. The combined pattern with EGFR classical mutation (EGFRcm) had worse PFS than the combined with EGFRum and single pattern (P, In a large‐scale multi‐center real‐world study in China, we detected and analyzed potential primary resistance to icotinib in EGFRum patients using the next‐generation sequencing (NGS) platform. EGFR extracellular domain mutation, BCL2L11 loss, PI3K‐AKT‐mTOR signaling pathway (PTEN, PIK3CA mutations), MET amplification, ERBB2 amplification or MYC amplification might contribute to primary resistance of icotinib in EGFRum NSCLC patients.

ROS1-rearranged non-small cell lung cancer (NSCLC) is a subset of NSCLC patients with unique malignant behavior and clinical course. Crizotinib, a multi-targeted ALK/ROS1/MET tyrosine kinase inhibitor (TKI), has promising significant activity in NSCLC with ROS1-rearrangement. The next-generation sequencing (NGS) is commonly used to identify the “druggable” genetic alterations in clinical practice. We identified a novel ROS1 fusion variant (FRK-ROS1) in a de novo stage IV NSCLC patient by NGS testing. This novel ROS1-rearrangement is generated by the fusion FRK to ROS1. The patient was remarkably responsive to crizotinib including the brain metastasis. A 29-year-old male never-smoker with chief complaints of back pain with a lumpy and flaky soft tissue mass in the upper right lobe of the lung and diffuse ground-glass shadow in both lungs e IV (cT4N3M1b). A CT-guided biopsy revealed the predominant adenocarcinoma and partial mucinous adenocarcinoma. By using next-generation sequencing (NGS) assay, we found that the tumor had FRK-ROS1 fusion rather than other actionable mutations. In that case, the patient took the first-line crizotinib and experienced a remarkable tumor response to it and tolerance well until written. FRK-ROS1 is a novel ROS1 fusion variant in NSCLC identified by NGS testing and the first-line crizotinib showed excellent performance in all lesions including the brain metastasis.

BACKGROUND: Chemotherapy is the major choice for advanced non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor exon 20 insertion (EGFR ex20ins). The efficacy of pemetrexed-based with other chemotherapy regimens and EGFR ex20ins subtypes in this population has not been well studied. METHODS: We screened patients with EGFR ex20ins by next-generation sequencing (NGS) from a large cohort. The clinicopathologic and medical information were collected in advanced NSCLC patients with EGFR ex20ins. We also compared the clinical outcomes among patients with different subtypes of EGFR ex20ins. RESULTS: We retrospectively collected 119 stage IIIB/IV NSCLC patients with EGFR ex20ins from 9142 NSCLC patients across China from June 2013 to December 2018. The subtypes of EGFR ex20ins included A767_V769dupASV (33/119, 27.73%), S768_D770dupSVD (19/119, 15.97%), N771_H773dupNPH (11/119, 9.24%), A763_Y764insFQEA (2/119, 1.68%) and others (54/119, 45.38%). A total of 64.7% (77/119) of patients received pemetrexed-based first-line chemotherapy and 13.45% (16/119) of patients received pemetrexed-based second-line chemotherapy. Pemetrexed-based chemo-treated patients had longer median progression-free survival (PFS) than patients without pemetrexed-based chemo-treated (5.5 vs. 3.0 months, P=0.0026). Survival data was available for 66 patients and the median overall survival (OS) was 24.7 months. Pemetrexed-based chemo-treated patients had longer OS tendency than patients without pemetrexed-based chemo-treated (25.0 vs. 19.6 months, P=0.0769). Patients harboring A767_V769dupASV had better OS than other subtypes of EGFR ex20ins but without statistical significance (P=0.0676). Multivariate analysis revealed that histological type of NSCLC and bone-metastasis before treatment were independent prognostic factors for OS in all patients after adjusting all characteristic and treatment factors (P

Based on WeChat applet, using portrait matching technology to help children find their suitable pet partners. Enhance the matching fit, design and implement the interactive appointment system. The applet mainly includes functions such as portrait matching, interactive reservation, foster care reservation and cloud development.

Background Primary malignant melanoma of the esophagus (PMME) is rare with high malignancy and poor prognosis. The aim of this study was to investigate the relationship between prognosis and clinicopathological characteristics of this disease. Methods A total of 9 patients with PMME were treated in Zhejiang Cancer Hospital between 2009 and 2019 retrospectively. According to 8th edition AJCC/UICC staging of cancers of the esophagus and esophagogastric junction, none of the patients were in stage I. However, 5 patients were in stage II, 2 patients were in stage III, and 2 patients were in stage IV at diagnosis. Five patients received surgery, while one of them received palliative resection. Three patients received postoperative chemotherapy; two of them (2/5) were diagnosed with recurrence. One patient in stage II received targeted therapy. One patient in stage III received first line chemotherapy and efficacy evaluation was stable disease (SD). Another one in stage III received biotherapy. One patient in stage IV received Chinese Medicine treatment and another received chemotherapy and palliative surgery. Results The 1-year disease-free survival (DFS) and overall survival (OS) rates of stage II who received surgery were 50% (2/4) and 100% (4/4) respectively. The 2-year DFS and OS rates were 50% (2/4) and 75% (3/4), respectively. However, patients with stage III–IV have a very poor prognosis. The 1-year OS is 0%. Conclusions Due to the small sample size, the statistic efficacy is low, but it can provide a certain theoretical basis for future research.

ROS1 rearrangement occurs in 1–2% of non-small cell lung cancer (NSCLC) cases. These patients would benefit from treatment with the anaplastic lymphoma kinase inhibitor, crizotinib; however, resistance to crizotinib inevitably develops in such patients despite an initial response. The mechanism of acquired resistance to crizotinib in patients with NSCLC with ROS1 rearrangement has not yet been identified. Herein, we report a case of a 66-year-old woman diagnosed with adenocarcinoma. PCR revealed no EGFR or ALK mutations. After the patient underwent several rounds of chemotherapy, crizotinib was administered. The disease explosively progressed six months later. A novel PIK3CA gene point mutation (p.L531P) was detected by next generation sequencing. This case is the second report of bypass activation conferred crizotinib resistance in a patient with NSCLC with ROS1-rearrangement, but is the first to confirm that activation of the mTOR signaling pathway leads to acquired crizotinib resistance.

Background c-MET has recently been identified as a promising novel target in non-small cell lung cancer (NSCLC). We detected the consistency of c-MET gene amplification in metastatic lymph nodes and tumor tissues of NSCLC patients and discuss the clinical application value of c-MET gene amplification in metastatic lymph nodes. Methods Real-time fluorescent quantitative PCR was used to test tumor tissues in 368 NSCLC patients and 178 paired metastatic lymph node samples. The amplification consistency in metastatic lymph nodes and tissue samples were compared and the correlation between c-MET gene amplification and the clinical characteristics of patients was analyzed. Results The c-MET gene amplification rate was 8.97% (33/368) in tumor tissues. Of the 178 paired cases, c-MET gene amplification was positive in 7.95% (15/178) of cancerous tissues and 18.54% (33/178) of metastatic lymph nodes. c-MET gene amplification was detected more frequently in metastatic lymph nodes than in primary cancerous tissue. When metastatic lymph nodes were used as surrogate samples of primary cancerous tissues, the sensitivity was 86.67% (13/15) and the specificity was 87.69% (143/163). Conclusions Screening for c-MET gene amplification in lymph node metastases could determine which patients are eligible for tyrosine kinase inhibitor therapy. Lymph node metastasis can predict c-MET gene amplification in a primary tumor and guide the clinical use of c-MET gene targeted drugs.

Anaplastic lymphoma kinase (ALK) rearrangement responds to ALK tyrosine kinase inhibitors (TKIs) in lung cancer. Many cases ultimately acquire resistance to crizotinib. Resistance, including ALK-dominant or ALK non-dominant, mechanisms have been described. Transformation to small-cell lung cancer is rare. Herein, we report a 49-year-old man diagnosed with adenocarcinoma, who was negative for EGFR and ALK genes as detected by reverse transcription polymerase chain reaction, and was treated with crizotinib. A new biopsy showed a small-cell lung cancer after disease progression. Then, next-generation sequencing (NGS) was carried out and detected a TP53 gene mutation, an ALK rearrangement, and no loss of the retinoblastoma gene (RB). Although a regimen for small-cell lung cancer may be one treatment option, a heterogeneous tumor may exist at the time of diagnosis and manifest during the course of disease.

Non-thyroid malignancies to the thyroid gland resulting from distant metastases are extremely rare, and such cases are rarely seen in clinical settings. The question of how a tumor metastasizes to the thyroid remains unanswered. Here we report a case of lung adenocarcinoma metastasizing to the thyroid gland. The article covers the pathological features, treatments, examination reports, and the postoperative follow-up reviews of the patient. In this article, we discuss the diagnostic method, the spread route, the prognosis, the mechanism and above all, the treatment. In addition, we searched the PubMed and ISI Web of Science databases for articles published in English using the key words "lung", "thyroid", and "metastasis", and we reviewed nearly all the reports about thyroid malignancies being metastasized from lung cancer. This rare case emphasizes the importance of the multifaceted comprehensiveness of the cephalometry diagnosis, pathological diagnosis, and immunohistochemical analysis to ensure that such rare cases are not missed. We declare that all cases of thyroid malignancies metastasized from the lungs shall be reported at large for further clinical research.

The response to icotinib in advanced non‐small cell lung cancers (NSCLC) with EGFR uncommon mutation (EGFRum) is unclear. Here we reported the efficacy and potential resistance mechanism of icotinib in Chinese EGFRum NSCLC patients. Between July 2013 and November 2016, 3117 NSCLC patients were screened for EGFRum in a multi‐center study in China. Circulating tumor DNA (ctDNA) was detected and analyzed using next‐generation sequencing (NGS) after progression from icotinib. The efficacy, safety and the potential resistance mechanism of icotinib were explored. After a median follow‐up of 6.2 months, 69 patients (70.41%) developed disease progression, the objective rate (ORR) and disease control rate (DCR) were 13.27% and 29.59% respectively, and the median progression‐free survival (PFS) was 5.5 months (95% CI: 1.2‐13.0 months). Both complex‐pattern with EGFR classical mutations (EGFRcm) and single‐pattern have better PFS than complex‐pattern without EGFRcm (median PFS was 7.2 (95% CI: 4.65‐9.75), 5.2 (95% CI: 3.24‐7.16) and 3.2 (95% CI: 2.97‐3.44) months, respectively, P, Better response to icotinib was observed in complex‐pattern with EGFRcm group. S768I mutation carriers may not benefit from icotinib. Acquired T790M mutation was common in icotinib‐resistant EGFRum NSCLC patients.

Background: NTRK gene fusions involving either NTRK1, NTRK2 or NTRK3 are oncogenic drivers of various solid tumor types but generally at a low frequency. TRK inhibitors such as LOXO-101, entrectinib, X396, AB-106, TL118 had remarkable and durable antitumor activities in patients (pts) with TRK fusion-positive cancers, regardless of age or tumor type. We assessed the frequency of NTRK fusions across 14, 491 advanced cancers to reveal the landscape in a wide variety of subtypes. Methods: A multicenter study in China was initiated from July 2013, and advanced cancer patients have been enrolled as of September 2018. We analyzed data from 14, 491 clinical advanced cancer cases, each of which had results from next-generation sequencing (NGS)-based 381 genes panel assay, analogous to the index patient. Results: Of this entire cohort [6837 lung cancer (47.18%), 1894 breast cancer (13.07%), 1325 colorectal cancer (9.14%), 312 soft tissue sarcoma (2.15%), 260 head and neck cancer (1.79%) and 1804 others (12.45%)], 40 patients were identified with NTRK fusions, including TPM3-NTRK1, LMNA-NTRK1, IRF2BP2-NTRK1, TPR-NTRK1, SQSTM1-NTRK1, C1orf111-NTRK1, NTRK1-CUL3, LIPI-NTRK1, NTRK1-C1orf61, TARDBP-NTRK1, LOC643387-NTRK1, NFASC-NTRK1, RFWD2-NTRK1, MSN-NTRK2, ATL2-NTRK2, AGTPBP1-NTRK2, ZCCHC7-NTRK2, CALR-NTRK2, ESRP1-NTRK2, ETV6-NTRK3. NTRK fusions were seen in 0.26% (18/6837) of lung cancer [C1orf111-NTRK1+TPM3-NTRK1(1), TPR-NTRK1(1), TPM3-NTRK1(2), SQSTM1-NTRK1+NTRK1-CUL3(1), LIPI-NTRK1(1), NTRK1-C1orf61(1), LMNA-NTRK1(1), MSN-NTRK2(1), TARDBP-NTRK1+LOC643387-NTRK1(1), IRF2BP2-NTRK1(1), ATL2-NTRK2 (1), NFASC-NTRK1(1), AGTPBP1-NTRK2(1), RFWD2-NTRK1(1), ZCCHC7-NTRK2(1), CALR-NTRK2(1) and ESRP1-NTRK2]; 0.21%(4/1894) of breast cancer [ETV6-NTRK3(4)]; 0.37%(5/1325) of colorectal cancer [TPM3-NTRK1(1), ETV6-NTRK3(4)]; 3.53%(11/312) of soft tissue sarcoma [LMNA-NTRK1(3), TPM3-NTRK1(1), ETV6-NTRK3(7)]; 0.38%(1/260) of head and neck cancer [ETV6-NTRK3(1)] and 0.05%(1/1804) of others [ETV6-NTRK3(1)]. Conclusion: NTRK fusions are a rare molecular subtype in Chinese solid tumors. The NTRK gene fusions more commonly occurred in NSCLC (0.3%), CRC (0.4%) and BC (0.2%), and may occur without other targetable alterations such as EGFR, ALK, ROS1. The clinical evidence for responsiveness of NTRK fusions driven solid tumors provides an opportunity to personalize treatments and improve clinical outcomes for patients (pts). Citation Format: Wen-xian Wang, Chun-wei Xu, Lei Lei, Xiao-jia Wang, You-cai Zhu, Yong Fang, Xiu-yu Cai, Rong-bo Lin, Li Lin, Hong Wang, Mei-yu Fang, Yin-bin Zhang, Shi-jie Lan, Xin Cai, Xin Liu, Xing-xiang Pu, Zong-yang Yu, Bing Wan, Jin-luan Li, Xian-bin Liang, Li-ping Wang, Wu Zhuang, Zi-yan Yang, Gang Chen, Tang-feng Lv, Yong Song. Large-scale study of NTRK fusions in Chinese solid tumors and using next generation sequencing: A multicenter study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 38.

For chondrosarcoma, metastasis to the thyroid gland is extremely rare. The diagnosis and treatment of thyroid metastasis from chondrosarcoma are discussed here. We found a case of thyroid malignancy occurring after treatment of chondrosarcoma. We reviewed patient characteristics, histological presentations on initial chondrosarcoma and thyroid metastasis, treatments, times of recurrence and death. In addition, we searched Embase, PubMed, and ISI Web of Science databases (1996–2018) for articles published in the English language using the key words “chondrosarcoma” and “thyroid” and we reviewed almost all the reports about thyroid metastasis from chondrosarcoma. Only 5 cases of chondrosarcoma metastases in the thyroid gland have been reported in the literature. We found that most patients are adults, with compression signs or pain, most of whom have poor prognoses. The main examinations are ultrasound, CT and fine needle aspiration biopsy, and primary treatment is surgery. These rare cases of chondrosarcoma presenting as a metastasis in the thyroid gland highlight the importance of close communication between radiologists, histopathologists, and clinicians to ensure that such exceptional cases are not missed.

Background c‐MET has recently been identified as a promising novel target in non‐small cell lung cancer (NSCLC). We detected the consistency of c‐MET gene amplification in metastatic lymph nodes and tumor tissues of NSCLC patients and discuss the clinical application value of c‐MET gene amplification in metastatic lymph nodes. Methods Real‐time fluorescent quantitative PCR was used to test tumor tissues in 368 NSCLC patients and 178 paired metastatic lymph node samples. The amplification consistency in metastatic lymph nodes and tissue samples were compared and the correlation between c‐MET gene amplification and the clinical characteristics of patients was analyzed. Results The c‐MET gene amplification rate was 8.97% (33/368) in tumor tissues. Of the 178 paired cases, c‐MET gene amplification was positive in 7.95% (15/178) of cancerous tissues and 18.54% (33/178) of metastatic lymph nodes. c‐MET gene amplification was detected more frequently in metastatic lymph nodes than in primary cancerous tissue. When metastatic lymph nodes were used as surrogate samples of primary cancerous tissues, the sensitivity was 86.67% (13/15) and the specificity was 87.69% (143/163). Conclusions Screening for c‐MET gene amplification in lymph node metastases could determine which patients are eligible for tyrosine kinase inhibitor therapy. Lymph node metastasis can predict c‐MET gene amplification in a primary tumor and guide the clinical use of c‐MET gene targeted drugs.

The aim of this meta-analysis is to evaluate the distribution pattern of KRAS and BRAF mutations in colorectal cancer.The database was searched without language restrictions. Meta-analyses were conducted using the STATA software. We calculated the odds ratio (OR) and its 95% confidence interval (95% CI) to estimate the distribution of and correlation between KRAS and BRAF mutations, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) in left- and right-sided colorectal cancer.The studies were divided into five groups: (1) distribution of KRAS/BRAF mutations in distal and proximal colorectal cancer, the summary OR value was 1.24 versus 4.03, (2) distribution of KRAS/BRAF mutations in CIMP-low/Neg and CIMP-high (CIMP-H) tumors, the summary OR value was 0.77 versus 10.49, (3) distribution of KRAS/BRAF mutations in MSI-low (MSI-L)/microsatellite stable (MSS) and MSI-high (MSI-H) tumors, the summary OR value was 0.51 versus 9.60, (4) proportion of CIMP-H/MSI-H tumors among distal and proximal colorectal tumors, the summary OR value was 3.66 versus 6.54, and (5) proportion of CIMP-H tumors among MSI-L/MSS and MSI-H tumors, the summary OR value was 5.87.The meta-analysis reveals that KRAS has a slightly higher mutation rate in MSI-L/MSS tumors. Moreover, BRAF mutations have higher detection rates in right-sided colorectal cancer, which suggests that BRAF mutations are likely in CIMP-H tumors. Therefore, based on these findings, the molecular diagnostic tests to be conducted in colorectal cancer patients can be determined according to the location/clinical features of the tumor.

The present study evaluated the efficacy and safety of maintenance therapy with oral etoposide following first-line docetaxel-cisplatin chemotherapy in patients with metastatic non-small cell lung cancer. The overall response rate in the docetaxel-cisplatin phase was 30.4%, with complete response of 0, partial response of 28, stable disease of 39. Maintenance chemotherapy with oral etoposide was given in 67 patients. No complete response was observed, but 10 patients presented with partial response and 45 with stable disease . The median time to progression was 5.0 months; median overall survival time was 10 months and the 1-year survival rate was 41% during the maintenance therapy. Therapy with oral etoposide was well tolerated with the hematologic toxicities, fatigue and oral mucositis being the most frequent side effects. Docetaxel-cisplatin chemotherapy followed by maintenance therapy with oral etoposide was well tolerated and moderately active against metastatic metastatic non-small cell lung cancer.

The aim of this study was to compare quantitative polymerase chain reaction (qPCR) with immunohistochemistry (IHC) for the detection of Her-2 in gastric cancer, and to investigate the correlation between the expression levels of human epidermal growth factor receptor 2 (Her-2) and clinical features. Clinical data from 426 cases of gastric cancer were collected. Her-2 expression levels in cancerous tissue were detected using IHC, and the Her-2/neu gene expression levels were determined by qPCR. The correlation between the expression level of Her-2 and clinical features was investigated. The positive expression rate of Her-2 in cancerous tissue detected using qPCR and IHC was 11.17% (46/412) and 13.38% (57/426), respectively. The positive expression of the Her-2 protein/gene was significantly correlated with the depth of invasion and lymphatic metastasis, as well as the TNM stage (P0.05). The diagnostic consistency was good between the two methods (κ=0.828). The results indicate that the expression of Her-2/neu is closely associated with the development of gastric cancer. qPCR is a convenient, objective and efficient method, which may be used as an alternative to IHC or fluorescence in situ hybridization for the detection of Her-2/neu gene.

To analysis the E protein epitopes of dengue virus type 1-4, Japanese encephalitis virus and yellow fever virus and to distinguish the shared or specific epitopes among them.Bioinformatic software DNAStar was used to analyze the hydrophilicity, flexibility, surface probability and antigenicity of dengue virus type 1-4, Japanese encephalitis virus and yellow fever virus E protein amino acid sequences. The influence of secondary structure was also considered. Based on the bio-informatic analysis of E protein epitopes, 6 specific epitopes were amplified and inserted into prokaryotic expression vector pMAL-c2x. The vectors was then transferred into E. coli BL21 (DE3) and Rosetta (DE3). Isopropyl-beta-D-thiogalactoside (IPTG) was used to induce the expression of gene segments and SDS-PAGE were used identify the expression proteins. The antigenicity was tested, using Western blot.15 shared epitopes and 47 specific epitopes were forecasted by bioinformatic analysis, and 6 specific epitopes from dengue virus type 1-4, Japanese encephalitis virus and yellow fever virus E protein were expressed in E. coli successfully. Two specific antigenic determinant from dengue virus type 1 and dengue virus type 2 were confirmed using Western blot, while the others epitopes shown no antigenic reaction property.Two specific antigenic determinant were confirmed, under Western blot.

To establish a specific, sensitive and practicable method for detection and typing of dengue virus.Based on the genomic sequence analysis of dengue virus types 1-4, 4 pairs of primers were designed. The specific capture probes of dengue virus types 1-4 were amplified using RT-PCR, cloned and sequenced before using them for precoating the microwell plate. The samples were amplified using biotin-labeled forward primer and reverse primer, and microwell plate hybridization was carried out for detection and typing of dengue virus types 1-4.The absorbance of the positive samples were higher than 0.5, while the average absorbance of the negative samples was lower than 0.1, with the S/N higher than 10.The method of PCR-ELISA we established for early detection and typing of all 4 dengue viruses seretypes.

To develop multiplex reverse translation-polymerase chain reaction (RT-PCR) method for detection of dengue virus type 1-4.Based on the genomes sequence analysis of dengue virus type 1-4, four-pair of primers were designed. The specificity of the primers was primarily tested by searching the GenBank DNA sequence database. The optimal reaction conditions of the multiplex RT-PCR were then established. The specificity of RT-PCR was tested using the homologous yellow fever virus and Japanese encephalitis virus. 30 serum samples of dengue virus from suspected sufferers in the prevalence of dengue virus in 2003 were detected using the methods we developed.Positive segments about 295, 237, 118, 347 bp could be seen in the multiplex RT-PCR production of dengue virus type 1-4, respectively. There were no positive segments in the RT-PCR productions of Japanese encephalitis virus and yellow fever virus. 25 of the 30 serum samples showed dengue virus type 1 positive results, while the sequencing results suggesting the amplification sequence having a high homology with dengue virus type 1 strain Cambodia, GD14/97 and GD05/99 (97%, 97%, 98%, respective).The method of multiplex RT-PCR we established could be used for early detection and identification of dengue virus type 1-4.

To identify the virus isolated from Jiangmen, Guangdong province and to discuss the possible origin.Using characteristics of indirect fluorescent antibody tests (IFA), reverse transcription-polymerase chain reaction (RT-PCR), mouse neurovirulence and cell culture to identify the isolated virus. According to the nature of dengue virus type 2 NGC strain, two pairs of primers were designed. The structural protein gene of isolated dengue virus type 2 strain was then amplified by RT-PCR, cloned into pMD18-T vector and sequenced.Twenty-two of 37 serum samples showed a positive reaction to dengue antibody IgG, and 36 of 37 with IgM with the highest antibody titer 1:640. Ten samples were resulted in a cytopathy on C6/36 cells and showed a neurovirulence in suckling mice when inoculated intracerebrally. The structural gene of new isolate GD19/2001 containing 2 325 nucleotides which encoded 774 amino acids. Data on nucleotide homology were 98%, 96%, 94%, 94%, 92%, 92%, 92% and 91% compared with TSV01, GD06/93, NGC and 44, ThNH81/93, 04 and GD08/98, and S1 respectively.The isolated virus from Jiangmen, Guangdong province belonged to dengue virus type 2, which might come from Australia.

Background Rapid identification and differentiation of mosquito-transmitted flaviviruses in acute-phase sera of patients and field-caught vector mosquitoes are important for the prediction and prevention of large-scale epidemics. Results We developed a flexible reverse-transcription loop-mediated isothermal amplification (RT-LAMP) unit for the detection and differentiation of dengue virus serotypes 1-4 (DENV1-4), Japanese encephalitis virus (JEV), and West Nile virus (WNV). The unit efficiently amplified the viral genomes specifically at wide ranges of viral template concentrations, and exhibited similar amplification curves as monitored by a real-time PCR engine. The detection limits of the RT-LAMP unit were 100-fold higher than that of RT-PCR in 5 of the six flaviviruses. The results on specificity indicated that the six viruses in the assay had no cross-reactions with each other. By examining 66 viral strains of DENV1-4 and JEV, the unit identified the viruses with 100% accuracy and did not cross-react with influenza viruses and hantaviruses. By screening a panel of specimens containing sera of 168 patients and 279 pools of field-caught blood sucked mosquitoes, results showed that this unit is high feasible in clinical settings and epidemiologic field, and it obtained results 100% correlated with real-time RT-PCR. Conclusions The RT-LAMP unit developed in this study is able to quickly detect and accurately differentiate the six kinds of flaviviruses, which makes it extremely feasible for screening these viruses in acute-phase sera of the patients and in vector mosquitoes without the need of high-precision instruments.