scholarly journals Analytical performance of a highly sensitive system to detect gene variants using next-generation sequencing for lung cancer companion diagnostics

Author(s):  
Kikuya Kato ◽  
Jiro Okami ◽  
Harumi Nakamura ◽  
Keiichiro Honma ◽  
Yoshiharu Sato ◽  
...  

Companion diagnostics, which predict the efficacy of molecular targeted agents based on genetic information, are indispensable for the treatment of advanced non-small cell lung carcinoma. Recent increase in the number of molecular targeted agents and the corresponding target genes have led to the demand for the simultaneous testing of multiple genes. Although gene panels using next-generation sequencing (NGS panels) are ideal for this purpose, conventional panels require high tumor content, and biopsy samples often do not meet this requirement. We developed a new NGS panel called a compact panel, to accommodate biopsy samples without the restriction of tumor content. The compact panel is characterized by high sensitivity, with detection limits for mutations of 0.14%, 0.20%, 0.48%, 0.24%, and 0.20% for EGFR exon 19 deletion, L858R, T790M, BRAF V600E, and KRAS G12C, respectively. Mutation detection also has a high quantitative ability, with correlation coefficients ranging from 0.966 to 0.992. The panel detected fusions in samples whose tumor cell content was as low as 1%. The compact panel exhibited good concordance with approved tests as follows: EGFR positive, 100.0 (95% confidence interval 95.5-100); EGFR negative, 90.9 (82.2-96.3); ALK positive, 96.7 (83.8-99.9); ALK negative, 98.4 (97.2-99.2); ROS1 positive, 100 (66.4-100); ROS1 negative, 99.0 (97.1-99.2); MET positive, 98.0 (89.0-100); MET negative 100 (92.8-100). The analytical performance demonstrated that the compact panel can handle various types of biopsy samples obtained by routine clinical practice, without requiring strict pathological monitoring like in case of conventional NGS panels.

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shunqiao Feng ◽  
Lin Han ◽  
Mei Yue ◽  
Dixiao Zhong ◽  
Jing Cao ◽  
...  

Abstract Background Langerhans cell histiocytosis (LCH) is a rare neoplastic disease that occurs in both children and adults, and BRAF V600E is detected in up to 64% of the patients. Several studies have discussed the associations between BRAF V600E mutation and clinicopathological manifestations, but no clear conclusions have been drawn regarding the clinical significance of the mutation in pediatric patients. Results We retrieved the clinical information for 148 pediatric LCH patients and investigated the BRAF V600E mutation using next-generation sequencing alone or with droplet digital PCR. The overall positive rate of BRAF V600E was 60/148 (41%). The type of sample (peripheral blood and formalin-fixed paraffin-embedded tissue) used for testing was significantly associated with the BRAF V600E mutation status (p-value = 0.000 and 0.000). The risk of recurrence declined in patients who received targeted therapy (p-value = 0.006; hazard ratio 0.164, 95%CI: 0.046 to 0.583). However, no correlation was found between the BRAF V600E status and gender, age, stage, specific organ affected, TP53 mutation status, masses close to the lesion or recurrence. Conclusions This is the largest pediatric LCH study conducted with a Chinese population to date. BRAF V600E in LCH may occur less in East Asian populations than in other ethnic groups, regardless of age. Biopsy tissue is a more sensitive sample for BRAF mutation screening because not all of circulating DNA is tumoral. Approaches with low limit of detection or high sensitivity are recommended for mutation screening to avoid type I and II errors.


2018 ◽  
Vol 3 (2) ◽  
pp. 178-184 ◽  
Author(s):  
M Rabie Al-Turkmani ◽  
Kelley N Godwin ◽  
Jason D Peterson ◽  
Gregory J Tsongalis

AbstractBackgroundMolecular tests have been increasingly used in the management of various cancers as more targeted therapies are becoming available as treatment options. The Idylla™ system is a fully integrated, cartridge-based platform that provides automated sample processing (deparaffinization, tissue digestion, and DNA extraction) and real-time PCR-based mutation detection with all reagents included in a single-use cartridge. This retrospective study aimed at evaluating both the Idylla KRAS and NRAS-BRAF-EGFR492 Mutation Assay cartridges (research use only) against next-generation sequencing (NGS) by using colorectal cancer (CRC) tissue samples.MethodsForty-four archived formalin-fixed paraffin-embedded (FFPE) CRC tissue samples previously analyzed by targeted NGS were tested on the Idylla system. Among these samples, 17 had a mutation in KRAS proto-oncogene, GTPase (KRAS), 5 in NRAS proto-oncogene, GTPase (NRAS), and 12 in B-Raf proto-oncogene, serine/threonine kinase (BRAF) as determined using the Ion AmpliSeq 50-gene Cancer Hotspot Panel v2. The remaining 10 samples were wild-type for KRAS, NRAS, and BRAF. Two 10-μm FFPE tissue sections were used for each Idylla run, 1 for the KRAS cartridge, and 1 for the NRAS-BRAF-EGFR492 cartridge. All cases met the Idylla minimum tumor content requirement for KRAS, NRAS, and BRAF (≥10%). Assay reproducibility was evaluated by testing commercial controls derived from human cell lines, which had an allelic frequency of 50% and were run in triplicate.ResultsThe Idylla system successfully detected all mutations previously identified by NGS in KRAS (G12C, G12D, G12V, G13D, Q61K, Q61R, A146T), NRAS (G12V, G13R, Q61H), and BRAF (V600E). Compared with NGS, Idylla had a sensitivity of 100%. Analysis of the mutated commercial controls demonstrated agreement with the expected result for all samples and 100% reproducibility. The Idylla system produced results quickly with a turnaround time of approximately 2 h.ConclusionThe Idylla system offers reliable and sensitive testing of clinically actionable mutations in KRAS, NRAS, and BRAF directly from FFPE tissue sections.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tyler Dang ◽  
Irene Lavagi-Craddock ◽  
Sohrab Bodaghi ◽  
Georgios Vidalakis

Citrus dwarfing viroid (CDVd) induces stunting on sweet orange trees [Citrus sinensis (L.) Osbeck], propagated on trifoliate orange rootstock [Citrus trifoliata (L.), syn. Poncirus trifoliata (L.) Raf.]. MicroRNAs (miRNAs) are a class of non-coding small RNAs (sRNAs) that play important roles in the regulation of tree gene expression. To identify miRNAs in dwarfed citrus trees, grown in high-density plantings, and their response to CDVd infection, sRNA next-generation sequencing was performed on CDVd-infected and non-infected controls. A total of 1,290 and 628 miRNAs were identified in stem and root tissues, respectively, and among those, 60 were conserved in each of these two tissue types. Three conserved miRNAs (csi-miR479, csi-miR171b, and csi-miR156) were significantly downregulated (adjusted p-value < 0.05) in the stems of CDVd-infected trees compared to the non-infected controls. The three stem downregulated miRNAs are known to be involved in various physiological and developmental processes some of which may be related to the characteristic dwarfed phenotype displayed by CDVd-infected C. sinensis on C. trifoliata rootstock field trees. Only one miRNA (csi-miR535) was significantly downregulated in CDVd-infected roots and it was predicted to target genes controlling a wide range of cellular functions. Reverse transcription quantitative polymerase chain reaction analysis performed on selected miRNA targets validated the negative correlation between the expression levels of these targets and their corresponding miRNAs in CDVd-infected trees. Our results indicate that CDVd-responsive plant miRNAs play a role in regulating important citrus growth and developmental processes that may participate in the cellular changes leading to the observed citrus dwarf phenotype.


Author(s):  
Qunxiong Pan ◽  
Jiangman Zhao ◽  
Mingzhu Li ◽  
Xiaoyu Liu ◽  
Yaping Xu ◽  
...  

Abstract An accurate biomarker or method for diagnosis of thyroid nodule with indeterminate fine-needle aspiration result is essential for clinical treatment. Micro RNAs (miRNAs) of exosomes are advantageous in the diagnosis of tumors because they are highly stable, and be protected by a bilayer membrane structure. Exosomes were isolated from 13 papillary thyroid carcinoma (PTC) and 7 nodular goiter (NG) patients’ plasma. Small RNA sequencing was performed on exosomes’ RNA in next-generation sequencing (NGS) platform. Then, we performed comprehensive analysis on miRNA expression profile in exosome of two groups. One hundred and twenty-nine differentially expressed miRNAs were identified in plasma exosomes between PTC and NG patients. Forty-nine miRNAs were up-regulated, and 80 miRNAs were down-regulated in PTC patients. Receiver operating characteristic (ROC) curves of 129 miRNAs were plotted. Area under curve (AUC) of 129 miRNAs was 0.571–0.951, with distribution peak of 0.82–0.86. AUC of 11 miRNAs was above 0.9, miR-5189-3p had the most optimal performance for diagnosis between PTC and NG, with 0.951 of AUC. Target genes of 129 miRNAs were enriched into 7 cancer-related signaling pathways, including mitogen-activated protein kinase (MAPK), tumor necrosis factor (TNF), NF-kappa B signaling pathway and so on. This study profiled the miRNA signature of exosomes from PTC patients and NG patients. We proposed a group of miRNAs in plasma exosomes as candidate biomarkers for thyroid nodule diagnosis.


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