BRACNAC: A BRCA1 and BRCA2 Copy Number Alteration Caller from Next-Generation Sequencing Data.

Detecting copy number variations (CNVs) and alterations (CNAs) in the BRCA1 and BRCA2 genes is essential for testing patients for targeted therapy applicability. However, the available bioinformatics tools were initially designed for identifying CNVs/CNAs in whole-genome or -exome (WES) NGS data or targeted NGS data without adaptation to the BRCA1/2 genes. Most of these tools were tested on sample cohorts of limited size, with their use restricted to specific library preparation kits or sequencing platforms. We developed BRACNAC, a new tool for detecting CNVs and CNAs in the BRCA1 and BRCA2 genes in NGS data of different origin. The underlying mechanism of this tool involves various coverage normalization steps complemented by CNV probability evaluation. We estimated the sensitivity and specificity of our tool to be 100% and 94%, respectively, with an area under the curve (AUC) of 94%. The estimation was performed using the NGS data obtained from 213 ovarian and prostate cancer samples tested with in-house and commercially available library preparation kits and additionally using multiplex ligation-dependent probe amplification (MLPA) (12 CNV-positive samples). Using freely available WES and targeted NGS data from other research groups, we demonstrated that BRACNAC could also be used for these two types of data, with an AUC of up to 99.9%. In addition, we determined the limitations of the tool in terms of the minimum number of samples per NGS run (≥20 samples) and the minimum expected percentage of CNV-negative samples (≥80%). We expect that our findings will improve the efficacy of BRCA1/2 diagnostics. BRACNAC is freely available at the GitHub server.

Detecting Microsatellite Instability in Endometrial, Colon, and Stomach Cancers Using Targeted NGS.

PURPOSE: To develop a method for testing the MSI based on targeted NGS. METHODS: Based on the results of previous studies, 81 microsatellite loci with high variability in MSI-H tumors were selected, and a method for calculating the MSI score was developed. Using the MSI score, we defined the MSI status in endometral (162), colon (153), and stomach (190) cancers. Accuracy of the MSI scores was evaluated by comparison with MMR immunohistochemistry for 137 endometrium (63 dMMR and 74 pMMR), 76 colon (29 dMMR and 47 pMMR), and 81 stomach (8 dMMR and 73 pMMR) cancers. RESULTS: Classification of MSS and MSI-H tumors was performed with AUC (0.99), sensitivity (92%), and specificity (98%) for all tumors without division into types. The accuracy of MSI testing in endometrial cancer was lower than for stomach and colon cancer (0.98, 87%, and 100%, respectively). The use of 27 loci only, the most informative for endometrial cancer, increased the overall accuracy (1.00, 99%, and 99%). Comparison of MSI score values in 505 tumors showed that MSI score is significantly higher in colon (p < 10-5) and stomach (p = 0.008) cancer compared with endometrial cancer. CONCLUSION: The MSI score accurately determines MSI status for endometrial, colon, and stomach cancers and can be used to quantify the degree of MSI.

Selection of IS6110 conserved regions for the detection of Mycobacterium tuberculosis using qPCR and LAMP.

IS6110 insertion sequence is a frequently used target for Mycobacterium tuberculosis detection. However, its sequence variability is studied insufficiently. We aimed to identify the most conservative and variable regions in IS6110 sequences and develop qPCR and LAMP oligonucleotide sets for the conservative regions. Using in-house Python scripts, 3609 M. tuberculosis genome sequences from the NCBI database were aligned; conservative regions were identified to design oligonucleotide sets. IS6110 fragments located within the 31-231 bp region were the most conservative and represented in genomes and were used to design qPCR and LAMP oligonucleotides. The in silico sensitivity of the qPCR oligonucleotides on the whole genome set was 99.1% and 98.4%. For the LAMP primers developed, the sensitivity was 96.9%. For qPCR, the limit of detection with 95% confidence (LoD95%) was four IS6110 copies per reaction, with LoD90% being 200 BCG cells per ml of artificial sputum. For LAMP, LoD95% was 16 copies per reaction, with LoD90% being 400 Mycobacterium bovis Bacille Calmette-Guerin (BCG) cells per ml of artificial sputum. We have demonstrated the IS6110 sequence variability and designed highly sensitive qPCR and LAMP oligonucleotides to detect M. tuberculosis.

A spectrum of BRCA1 and BRCA2 germline deleterious variants in ovarian cancer in Russia.

PURPOSE: Pathogenic variants (PVs) in BRCA1 and BRCA2 genes are essential biomarkers of an increased breast and ovarian cancer risk and tumor sensitivity to poly ADP ribose polymerase inhibitors. In Russia, eight PVs were thought to be the most common, among which BRCA1 c.5266dup is the most frequently identified one. METHODS: We show the distribution of BRCA1/2 PVs identified with quantitative PCR and targeted next-generation sequencing in 1399 ovarian cancer patients recruited into the study from 72 Russian regions in 2015-2021. RESULTS: The most abundant PVs were c.5266dup (41.0%), c.4035del (7.0%), c.1961del (6.3%), c.181 T > G (5.2%), c.3756_3759del (1.8%), c.3700_3704del (1.5%), and c.68_69del (1.5%), all found in BRCA1 and known to be recurrent in Russia. Several other frequent PVs were identified: c.5152 + 1G > T (1.2%), c.1687C > T (1.0%), c.4689C > G (0.9%), c.1510del (0.6%), c.2285_2286del (0.6%) in the BRCA1 gene; and c.5286 T > G (1.2%), c.2808_2811del (0.8%), c.3847_3848del (0.8%), c.658_659del (0.7%), c.7879A > T (0.6%), in the BRCA2 gene. For the most common PV in the BRCA2 gene c.5286 T > G, we suggested that it arose about 700 years ago and is a new founder mutation. CONCLUSION: This study extends our knowledge about the BRCA1 and BRCA2 pathogenic variants variability.

Appearances are deceptive: Three RNA viruses co-infected with the nucleopolyhedrovirus in host Lymantria dispar.

The virus infection, which visually looks like typical monoinfection, in fact may hide a great complex of different species. Without detailed analysis, we may miss the important interaction between pathogens, including new species. In the current study, we found the new species inside the mix of cubic and polyhedral occlusion bodies (OBs) isolated from the gypsy moth, Lymantria dispar L. (Ld). Transmission electron microscopy (TEM) revealed that into the one cadaver were OBs which belonged to baculovirus and cypoviruses. The baculovirus produced polyhedral OBs, while cypoviruses produced polyhedral and cubic OBs. Genomic analysis detected the multiple Ld nucleopolyhedroviruses, and cypoviruses were Hubei lepidoptera virus 3 and Dendrolimus punctatus cypovirus 1. This represents the first isolation of the Hubei lepidoptera virus 3 from the gypsy moth, proposed as "Lymantria dispar cypovirus 3". The RNAseq analysis also revealed the presence of Lymantria dispar iflavirus 1. The insecticidal activity of the mixed infection was comparable to that of typical baculovirus monoinfection. Thus, we demonstrate that i) the shape of OBs identified by light microscopy cannot be a robust indicator of viral species infecting the host; ii) only specific analysis may reveal the true composition of viral infection.

NGS-PrimerPlex: High-throughput primer design for multiplex polymerase chain reactions.

Multiplex polymerase chain reaction (PCR) has multiple applications in molecular biology, including developing new targeted next-generation sequencing (NGS) panels. We present NGS-PrimerPlex, an efficient and versatile command-line application that designs primers for different refined types of amplicon-based genome target enrichment. It supports nested and anchored multiplex PCR, redistribution among multiplex reactions of primers constructed earlier, and extension of existing NGS-panels. The primer design process takes into consideration the formation of secondary structures, non-target amplicons between all primers of a pool, primers and high-frequent genome single-nucleotide polymorphisms (SNPs) overlapping. Moreover, users of NGS-PrimerPlex are free from manually defining input genome regions, because it can be done automatically from a list of genes or their parts like exon or codon numbers. Using the program, the NGS-panel for sequencing the LRRK2 gene coding regions was created, and 354 DNA samples were studied successfully with a median coverage of 97.4% of target regions by at least 30 reads. To show that NGS-PrimerPlex can also be applied for bacterial genomes, we designed primers to detect foodborne pathogens Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus considering variable positions of the genomes.

BRCA-analyzer: Automatic workflow for processing NGS reads of BRCA1 and BRCA2 genes.

The use of targeted next-generation sequencing (NGS) provides great new opportunities for molecular and medical genetics. However, in order to take advantage of these opportunities, we need to have reliable tools for extracting the necessary information from the huge amount of data generated by NGS. Here we present our automatic multithreaded workflow for processing NGS data of BRCA1 and BRCA2 genes obtained with NGS technology named BRCA-analyzer. Optimizing it on the sequencing data of 899 samples from 693 patients, we were able to find the most reliable tools and adjust their parameters in such a way that all pathogenic variants found were confirmed by Sanger's sequencing. For 82 and 24 DNA samples from blood and formalin-fixed paraffin-embedded blocks, NGS libraries were prepared with GeneRead BRCA panel v2 (Qiagen). The reads obtained were processed with BRCA-analyzer and Qiagen GeneRead Data analysis workflow. In total 27 pathogenic variants were found and confirmed by Sanger's sequencing, with all of them determined with BRCA-analyzer. Qiagen GeneRead Data analysis discarded 5 true pathogenic variants due to their location in homopolymeric sequence stretches. For other 793 samples, libraries were prepared by the in-house method, and NGS data were analyzed by BRCA-analyzer in comparison to another free automatic amplicon NGS workflow Canary. From total 137 pathogenic variations, BRCA-analyzer found 135 and Canary 123. Mutations were missed by BRCA-analyzer due to the trimming primer sequences from reads before mapping to be fixed in the next version. On the freely available NGS data, we showed that BRCA-analyzer could also be used for hybrid capture gene panels, although it needs more extensive testing on such library preparation methods. Thus, BRCA-analyzer is an automatic workflow for processing NGS data of BRCA1/2 genes with variant filters adapted to amplicon-based targeted NGS data. BRCA-analyzer can be used to identify germline as well as somatic mutations. BRCA-analyzer is freely available at https://github.com/aakechin/BRCA-analyzer.

Highly Sensitive and Reliable Detection of EGFR Exon 19 Deletions by Droplet Digital Polymerase Chain Reaction.

BACKGROUND: Analysis of EGFR mutations is becoming a routine clinical practice but the optimal EGFR mutation testing method is still to be determined. METHODS: We determined the nucleotide sequence of deletions located in exon 19 of the EGFR gene in lung tumor samples of patients residing in different regions of Russia (153 tumor DNA specimens), using Sanger sequencing. We developed a droplet digital polymerase chain reaction assay capable of detecting all common EGFR deletions in exon 19. We also compared the therascreen amplification refractory mutation system assay with a droplet digital polymerase chain reaction assay for the detection of all the deletions in our study. RESULTS: The droplet digital polymerase chain reaction assay demonstrated 100% sensitivity against polymerase chain reaction fragment length analysis and detected all possible types of deletions revealed in our study (22 types). At the same time, the therascreen EGFR RGQ PCR Kit was not able to detect deletions c.2252-2276>A and c.2253-2276 and showed low performance for another long deletion. CONCLUSION: Thus, we can conclude that the extraordinary length of deletions and their atypical locations (shift at the 3'-region compared to known deletions) could be problematic for the therascreen EGFR RGQ PCR Kit and should be taken into account during targeted mutation test development. However, droplet digital polymerase chain reaction is a promising and reliable assay that can be used as a diagnostic tool to genotype formalin-fixed paraffin-embedded cancer samples for EGFR or another clinically relevant somatic mutation.