BRAF mutation testing with a rapid, fully integrated molecular diagnostics system.

Fast and accurate diagnostic systems are needed for further implementation of precision therapy of BRAF-mutant and other cancers. The novel IdyllaTMBRAF Mutation Test has high sensitivity and shorter turnaround times compared to other methods. We used Idylla to detect BRAF V600 mutations in archived formalin-fixed paraffin-embedded (FFPE) tumor samples and compared these results with those obtained using the cobas 4800 BRAF V600 Mutation Test or MiSeq deep sequencing system and with those obtained by a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory employing polymerase chain reaction-based sequencing, mass spectrometric detection, or next-generation sequencing. In one set of 60 FFPE tumor samples (15 with BRAF mutations per Idylla), the Idylla and cobas results had an agreement of 97%. Idylla detected BRAF V600 mutations in two additional samples. The Idylla and MiSeq results had 100% concordance. In a separate set of 100 FFPE tumor samples (64 with BRAF mutation per Idylla), the Idylla and CLIA-certified laboratory results demonstrated an agreement of 96% even though the tests were not performed simultaneously and different FFPE blocks had to be used for 9 cases. The IdyllaTMBRAF Mutation Test produced results quickly (sample to results time was about 90 minutes with about 2 minutes of hands on time) and the closed nature of the cartridge eliminates the risk of PCR contamination. In conclusion, our observations demonstrate that the Idylla test is rapid and has high concordance with other routinely used but more complex BRAF mutation-detecting tests.

Multi-center evaluation of the novel fully-automated PCR-based Idylla™ BRAF Mutation Test on formalin-fixed paraffin-embedded tissue of malignant melanoma.

The advent of BRAF-targeted therapies led to increased survival in patients with metastatic melanomas harboring a BRAF V600 mutation (implicated in 46-48% of malignant melanomas). The Idylla(™) System (Idylla(™)), i.e., the real-time-PCR-based Idylla(™) BRAF Mutation Test performed on the fully-automated Idylla(™) platform, enables detection of the most frequent BRAF V600 mutations (V600E/E2/D, V600K/R/M) in tumor material within approximately 90 min and with 1% detection limit. Idylla(™) performance was determined in a multi-center study by analyzing BRAF mutational status of 148 archival formalin-fixed paraffin-embedded (FFPE) tumor samples from malignant melanoma patients, and comparing Idylla(™) results with assessments made by commercial or in-house routine diagnostic methods. Of the 148 samples analyzed, Idylla(™) initially recorded 7 insufficient DNA input calls and 15 results discordant with routine method results. Further analysis learned that the quality of 8 samples was insufficient for Idylla(™) testing, 1 sample had an invalid routine test result, and Idylla(™) results were confirmed in 10 samples. Hence, Idylla(™) identified all mutations present, including 7 not identified by routine methods. Idylla(™) enables fully automated BRAF V600 testing directly on FFPE tumor tissue with increased sensitivity, ease-of-use, and much shorter turnaround time compared to existing diagnostic tests, making it a tool for rapid, simple and highly reliable analysis of therapeutically relevant BRAF mutations, in particular for diagnostic units without molecular expertise and infrastructure.

Human papillomavirus multiplex ligation-dependent probe amplification assay for the assessment of viral load, integration, and gain of telomerase-related genes in cervical malignancies.

We evaluated the reliability of a novel multiplex ligation-dependent probe amplification (MLPA) assay in detecting integration of human papillomavirus (HPV) based on the viral E2/E6 copy number ratio in formalin-fixed and paraffin-embedded cervical lesions. The MLPA results were compared with those of amplification of papillomavirus oncogene transcripts for RNA, detection of integrated papillomavirus sequences for DNA, and HPV fluorescence in situ hybridization (FISH). DNA was isolated from 41 formalin-fixed and paraffin-embedded HPV-positive cervical lesions (cervical intraepithelial neoplasia grade 3 lesions, squamous cell carcinomas, and adenocarcinomas) for MLPA analysis. From 13 matching frozen samples, DNA and RNA were isolated for the detection of integrated papillomavirus sequences and/or the amplification of papillomavirus oncogene transcripts, respectively. Integrated HPV16, HPV18, or both were identified. The MLPA assay detected viral integration in 12 of these 13 cases, and episomal copies also were detected in 7 cases. In 20 of the 24 cases with exclusive viral integration or episomal viral copies as detected by FISH, MLPA confirmed the physical status of the virus. In the cases classified as mixed by FISH, the presence of excess episomal copies complicated the recognition of viral integration by MLPA. Furthermore, the feasibility of detecting gain of the telomerase genes with the HPV MLPA assay was evaluated. The MLPA confirmed the FISH data in 12 of 13 cases in which the status of copy number gain for telomerase RNA component was known. In conclusion, the HPV MLPA assay can be performed on routinely processed cervical lesions for the detection of viral load and HPV integration.

Use of the HPV MLPA assay in cervical cytology for the prediction of high grade lesions.

Current screening methods for uterine cervical cancer such as Papanicolaou smears and/or high risk human Papillomavirus (HR-HPV) detection have a high negative predictive value but a low positive predictive value for the presence of high grade cervical lesions. Therefore, new parameters are needed to reduce the rate of unnecessary referrals for colposcopy. The predictive value of the HPV multiplex ligation-dependent probe amplification (MLPA) assay, which can assess simultaneously HPV16/18 viral load and viral integration, was evaluated. The assay was applied to 170 cervical cytological samples, and the results were correlated with the matching histological follow-up. The GP5+/6+ assay and qPCR were used as a control for HR-HPV typing. The MLPA assay classified a higher percentage of cases as high-risk (high-viral load and/or viral integration) with higher grades of dysplasia. There was a high correlation between the HPV MLPA assay and qPCR for viral load and HPV genotyping, and between the MLPA assay and the GP5+/6+ assay for HPV genotyping. The sensitivity and specificity of the HPV MLPA assay for the detection of high-grade lesions were 44% and 93%, respectively. This study demonstrates that the HPV MLPA assay can reliably detect HPV 16/18, viral load, and viral integration in cytological samples. Also, high-risk classification correlated well with the presence of high-grade dysplasia. However, for the implementation of the MLPA assay into clinical practice, additional HR-HPV types need to be included to increase the sensitivity of the assay, and thereby increase its negative predictive value.

Evaluation of a new multiplex polymerase chain reaction assay STDFinder for the simultaneous detection of 7 sexually transmitted disease pathogens.

We evaluated a new multiplex polymerase chain reaction (mPCR), "STDFinder assay", a novel multiplex ligation-dependent probe amplification (MLPA) assay for the simultaneous detection of 7 clinically relevant pathogens of STDs, i.e., Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma genitalium, Treponema pallidum, and herpes simplex virus type 1 and 2 (HSV-1 and HSV-2). An internal amplification control was included in the mPCR reaction. The limits of detection for the STDFinder assay varied among the 7 target organisms from 1 to 20 copies per MLPA assay. There were no cross-reactions among any of the probes. Two hundred and forty-two vaginal swabs and an additional 80 specimens with known results for N. gonorrhoeae and C. trachomatis, obtained from infertile women seen at an infertility research clinic at the Kigali Teaching Hospital in Rwanda, were tested by STDFinder assay and the results were confirmed by single real-time PCR using different species-specific targets. Compared to the reference standard, the STDFinder assay showed specificities and sensitivities of 100% and 100%, respectively, for N. gonorrhoeae, C. trachomatis, and M. genitalium; 90.2% and 100%, respectively, for Trichomonas vaginalis; and 96.1% and 100%, respectively, for HSV-2. No specimen was found to be positive for HSV-1 by either the STDFinder assay or the comparator method. Similarly, the sensitivity for Treponema pallidum could not be calculated due to the absence of any Treponema pallidum-positive samples. In conclusion, the STDFinder assays have comparable clinical sensitivity to the conventional mono and duplex real-time PCR assay and are suitable for the routine detection of a broad spectrum of these STDs at relatively low cost due to multiplexing.

Increase in viral load, viral integration, and gain of telomerase genes during uterine cervical carcinogenesis can be simultaneously assessed by the HPV 16/18 MLPA-assay.

Oncogenic human papillomavirus (HPV) infection is the most important risk factor in cervical carcinogenesis cases; high viral loads, viral integration into the host genome, and gain of the telomerase-related genes, TERT and TERC, are all factors associated with progression to cancer. A recently developed multiparameter HPV 16/18 multiplex ligation-dependent probe amplification (MLPA) assay, which allows the simultaneous assessment of these factors, was applied to a series of 67 normal and (pre)malignant frozen uterine cervical samples, as well as to 91 cytological preparations, to test the ability of the MLPA assay to identify high-risk lesions on the basis of these factors. Validation was performed using quantitative PCR, the PapilloCheck and fluorescence in situ hybridization. Only 5 out of 37 normal tissue samples or low-grade cervical lesions (ie, CIN1 and condyloma) showed either an HPV16 viral load higher than 25 copies per cell, viral integration, and/or gain of one of the telomerase-related genes, whereas for the high-grade cervical lesions, one or more of these risk factors was found in 25 of 30 cases. The HPV MLPA assay showed a sensitivity of 83% and a specificity of 86% in frozen cervical specimens. Furthermore, the feasibility of the MLPA assay was shown for cytological samples, where in 57% of high-grade squamous intraepithelial lesion cases, the high-risk factors were detected using this assay.

A new multiparameter assay to assess HPV 16/18, viral load and physical status together with gain of telomerase genes in HPV-related cancers.

Oncogenic human papillomavirus (HPV) is the most important risk factor for cancer of the uterine cervix and a subgroup of head and neck cancers. Viral load has been associated with persistence of infection, whereas integration of HPV into the host cell genome is associated with transition to invasive disease. Viral integration is frequently correlated with loss of viral E2 and gain of the telomerase-related genes TERC and TERT. The objective of this study was to develop a rapid and sensitive multiplex ligation-dependent probe amplification (MLPA) assay for the simultaneous analysis of viral load, integration and copy number gain of TERC and TERT in HPV16/18-associated lesions. The performance of the assay was tested for HPV vs. human gene copy number ratios ranging from 0.1 to 100 and for percentages of integration ranging from 0 to 100%. The model systems used include plasmid mixtures and the HPV-positive cell lines SiHa, HeLa and CaSki described to contain a range of 2-600 viral copies per cell. In samples with low-viral load, viral integration can be reliably determined when more than 30% of the virus is integrated. Gain of the telomerase-related genes in the cell lines as determined by our MLPA assay was in accordance with data reported in the literature. Our study demonstrates that within a single MLPA-reaction viral type, load, integration and gain of TERC and TERT can be reliably determined, which will improve risk assessment for patients suspected for HPV infection.

RespiFinder: a new multiparameter test to differentially identify fifteen respiratory viruses.

Broad-spectrum analysis for pathogens in patients with respiratory tract infections is becoming more relevant as the number of potential infectious agents is still increasing. Here we describe the new multiparameter RespiFinder assay, which is based on the multiplex ligation-dependent probe amplification (MLPA) technology. This assay detects 15 respiratory viruses in one reaction. The MLPA reaction is preceded by a preamplification step which ensures the detection of both RNA and DNA viruses with the same specificity and sensitivity as individual monoplex real-time reverse transcription-PCRs. The RespiFinder assay was validated with 144 clinical samples, and the results of the assay were compared to those of cell culture and a respiratory syncytial virus (RSV)-specific immunochromatography assay (ICA). Compared to the cell culture results, the RespiFinder assay showed specificities and sensitivities of 98.2% and 100%, respectively, for adenovirus; 96.4% and 100%, respectively, for human metapneumovirus; 98.2% and 100%, respectively, for influenza A virus (InfA); 99.1% and 100%, respectively, for parainfluenza virus type 1 (PIV-1); 99.1% and 80%, respectively, for PIV-3; 90.1% and 100%, respectively, for rhinovirus; and 94.6% and 100%, respectively, for RSV. Compared to the results of the RSV-specific ICA, the RespiFinder assay gave a specificity and a sensitivity of 82.4% and 80%, respectively. PIV-2, PIV-4, influenza B virus, InfA H5N1, and coronavirus 229E were not detected in the clinical specimens tested. The use of the RespiFinder assay resulted in an increase in the diagnostic yield compared to that obtained by cell culture (diagnostic yields, 60% and 35.5%, respectively). In conclusion, the RespiFinder assay provides a user-friendly and high-throughput tool for the simultaneous detection of 15 respiratory viruses with excellent overall performance statistics.

Toxin profiles and resistances to macrolides and newer fluoroquinolones as epidemicity determinants of clinical isolates of Clostridium difficile from Warsaw, Poland.

Amplified fragment length polymorphism genotypes, antibiotic resistance profiles, and toxin profiles of Clostridium difficile strains from Warsaw were determined. The isolates segregate in six major genotypes, coinciding with toxin profiles. Most of the toxin A-negative toxin B-positive toxin CDT-negative strains possess ermB, and several strains were resistant to fluoroquinolones. Resistograms and toxin types of C. difficile strains are epidemicity determinants.

A new high-throughput AFLP approach for identification of new genetic polymorphism in the genome of the clonal microorganism Mycobacterium tuberculosis.

We have here applied high-throughput amplified fragment length polymorphism (htAFLP) analysis to strains belonging to the five classical species of the Mycobacterium tuberculosis complex. Using 20 strains, three enzyme combinations and eight selective amplification primer pairs, 24 AFLP reactions were performed per strain. Overall, this resulted in 480 DNA fingerprints and more than 1200 htAFLP-amplified PCR fragments were visualised per strain. The cumulative dendrogram correctly clustered strains from the various species, albeit within a distance of 6.5% for most of them. The single isolate of Mycobacterium canettii presented separately at 19% distance. All over, 169 fragments (14%) appeared to be polymorphic. Sixty-eight were specific for M. canetti and forty-five for Mycobacterium bovis. For the 10 different M. tuberculosis strains included in the present analysis, 56 polymorphic markers were identified. Upon sequencing 20 of these marker regions and comparisons with the H37Rv genome sequence, 25% appeared to share homology to members of the antigenically variable PE/PPE surface protein encoding gene family confirming previous findings on the genetic heterogeneity within these genes. In addition, homologues for phage genes and insertion element-encoded genes were detected. Forty-five percent of the sequences derived from ORFs with a currently unknown function, which was corroborated by genome sequence comparison for the clinical M. tuberculosis CD 1551 isolate. Sequence variation in M. tuberculosis was assessed in more detail for a subset of these loci by newly designed PCR restriction fragment length polymorphism (RFLP) tests and direct sequencing. Fourteen novel PCR RFLP tests were developed and twelve novel single nucleotide polymorphisms (SNPs) were identified, all suited for epidemiological analysis of M. tuberculosis. The tests allowed for identification of the major Mycobacterium species and M. tuberculosis variants and clones.

Quantitative comparison of cDNA-AFLP, microarrays, and GeneChip expression data in Saccharomyces cerevisiae.

cDNA-AFLP is a genome-wide expression analysis technology that does not require any prior knowledge of gene sequences. This PCR-based technique combines a high sensitivity with a high specificity, allowing detection of rarely expressed genes and distinguishing between homologous genes. In this report, we validated quantitative expression data of 110 cDNA-AFLP fragments in yeast with DNA microarrays and GeneChip data. The best correlation was found between cDNA-AFLP and GeneChip data. The cDNA-AFLP data revealed a low number of inconsistent profiles that could be explained by gel artifact, overexposure, or mismatch amplification. In addition, 18 cDNA-AFLP fragments displayed homology to genomic yeast DNA, but could not be linked unambiguously to any known ORF. These fragments were most probably derived from 5' or 3' noncoding sequences or might represent previously unidentified ORFs. Genes liable to cross hybridization showed identical results in cDNA-AFLP and GeneChip analysis. Three genes, which were readily detected with cDNA-AFLP, showed no significant expression in GeneChip experiments. We show that cDNA-AFLP is a very good alternative to microarrays and since no preexisting biological or sequence information is required, it is applicable to any species.