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Background Microsatellite instability (MSI) is now being used as a sole biomarker to guide immunotherapy treatment for men with advanced prostate cancer. Yet current molecular diagnostic tests for MSI have not been evaluated for use in prostate cancer. Methods We evaluated two next-generation sequencing (NGS) MSI-detection methods, MSIplus (18 markers) and MSI by Large Panel NGS (> 60 markers), and compared the performance of each NGS method to the most widely used 5-marker MSI-PCR detection system. All methods were evaluated by comparison to targeted whole gene sequencing of DNA mismatch-repair genes, and immunohistochemistry for mismatch repair genes, where available. Results In a set of 91 prostate tumors with known mismatch repair status (29-deficient and 62-intact mismatch-repair) MSIplus had a sensitivity of 96.6% (28/29) and a specificity of 100% (62/62), MSI by Large Panel NGS had a sensitivity of 93.1% (27/29) and a specificity of 98.4% (61/62), and MSI-PCR had a sensitivity of 72.4% (21/29) and a specificity of 100% (62/62). Conclusions We found that the widely used 5-marker MSI-PCR panel has inferior sensitivity when applied to prostate cancer and that NGS testing with an expanded panel of markers performs well. In addition, NGS methods offer advantages over MSI-PCR, including no requirement for matched non-tumor tissue and an automated analysis pipeline with quantitative interpretation of MSI-status.

ObjectivesOur study was designed to assess whether paired normal-tumour testing increased access to targeted therapy, clinical trials and influenced cancer screening recommendations given to patients and their families.DesignProspective cohort study.SettingAcademic cancer centre in the Pacific Northwest region of the USA.ParticipantsPatients newly diagnosed between 01 January 2021 and 31 December 2022 with cancers of the oesophagus, gastro-oesophageal junction and stomach (CEGEJS) were included. All other cancer diagnoses such as head and neck, duodenal and lower gastrointestinal tract cancers were excluded.InterventionPaired germline and tumour genetic test within 90 days of new patient visit.Primary outcome measuresNumber of targeted therapies received (or not) when eligible, follow-up treatment data and number of inherited predispositions to cancers identified. No secondary outcome measures.ResultsOf 42 patients, 32 (76.2%) were eligible for at least one targeted therapy. 19 patients received immunotherapy, when 16 had a biomarker predicting immunotherapy benefit, and benefit of immunotherapy was unclear for 3. Another 11 did not have this biomarker, and 6 of them received immunotherapy. Six pathogenic variants were identified in four high-risk genes. By 01 January 2024, 18 patients (42.9%) had died of complications of cancer.ConclusionMore than 75% of patients who received tumour testing were eligible for a targeted therapy regardless of their stage at diagnosis, emphasising the need to expand access to testing with staging workup to improve survival outcomes. Six families received personalised screening recommendations, thanks to this study.

Neuroendocrine transformation (NT) in cancers, typically observed under the selective pressure of targeted therapies, involves lineage plasticity where adenocarcinomas adopt neuroendocrine characteristics while retaining the molecular alterations of their original histology. This phenomenon, well-documented in prostate and lung cancers, has not been observed in gynecological malignancies until now. We present two pivotal cases involving primary ovarian and uterine cancers that developed neuroendocrine carcinomas post-treatment. Initially presumed to be independent primaries, comprehensive next-generation sequencing technologies, including UW-OncoPlex and BROCA panels, were used to establish a clonal relationship between the primary tumors and their respective neuroendocrine metastases. This report provides the first documented instances of NT in gynecological cancers, indicating that it may be a more widespread resistance mechanism than previously recognized. Routine re-biopsy and early integration of advanced molecular diagnostics into clinical practice will identify NT and provide insights into pathogenesis and eventual therapeutic options.

BackgroundNapsin A is normally expressed in human lung pneumocytes and is a highly expressed cancer antigen in lung adenocarcinoma. We examined whether T cells specific for Napsin A may play a role in immune checkpoint inhibitor (ICI)-mediated responses. We used bulk T-cell receptor (TCR) repertoire data to assess whether the presence of Napsin A-specific clonotypes in the peripheral blood was associated with improved clinical responses to ICI.MethodsPatients with metastatic non-small cell lung cancer (NSCLC) receiving anti-programmed cell death protein 1 (PD-1) and/or programmed death-ligand 1 (PD-L1) were enrolled at Fred Hutchinson Cancer Center and Stanford University Medical Center (n=62; histology of adenocarcinoma n=48, squamous n=9, NSCLC/other n=5). Peripheral blood mononuclear cells were collected for genomic DNA isolation at one pretreatment and one post-treatment time point (range 3 weeks to 3 months). TCRβ was bulk sequenced via the immunoSEQ platform (Adaptive Biotechnologies). Napsin A-specific TCRβ sequences were identified from publicly available data and their frequencies were quantified in each patient sample. We examined whether overall survival (OS) and progression-free survival (PFS) outcomes differed in patients with or without detectable Napsin A-specific TCRs (herein Napsin TCRs). We used Cox proportional hazards regression to assess the association between detectable Napsin TCRs and PFS or OS in univariable and multivariable analyses.ResultsNapsin TCRs were detectable in the blood in a large fraction of our cohort (n=25/62 (40%) pretreatment; n=21/42 (50%) post-treatment). Patients with detectable Napsin TCRs had a significant improvement in OS compared with patients without these TCRs (median OS 45.4 vs 14.8 months, p=0.0043 pretreatment; median OS 55.4 vs 18.9 months, p=0.0066 post-treatment). Among 27 HLA-A*02 carriers of 55 human leukocyte antigen-typed patients (49%), patients with detectable pretreatment Napsin TCRs had a significant improvement in OS (median 60.2 vs 16.5 months, p=0.0054) and PFS (median 21.5 vs 7.2 months, p=0.031) compared with patients without these TCRs. In univariate and multivariate analysis, the presence of Napsin TCRs pretreatment was associated with improved OS (p=0.0057, HR 0.40, 95% CI 0.21 to 0.76 univariate; p=0.033, HR 0.45, 95% CI 0.23 to 0.91 multivariate).ConclusionsNapsin TCRs are frequently detected in patients with NSCLC and are associated with improved OS in patients with NSCLC receiving ICI.

Background and Aims: Multiple laboratory methods are used to screen patients with colorectal cancer (CRC) for mismatch repair (MMR) protein deficiency to identify possible Lynch syndrome patients. The goal of this study was to compare the agreement between ready-to-use immunohistochemistry (IHC) assays for MLH-1, PMS-2, MSH-2, MSH-6, and mutated BRAF at V600E and molecular methods in CRC cases. The inclusion of the BRAF V600E mutation testing is important for the identification of patients with sporadic CRC, as the BRAF V600E mutation is very rarely observed in patients with Lynch syndrome tumors. Methods: CRC cases were analyzed by ColoSeqTM tumor sequencing assay and VENTANA MMR IHC Panel that included anti-MLH1, anti-PMS2, anti-MSH2, anti-MSH6, and anti-BRAF V600E antibodies. Additionally, CRC cases with MLH1 IHC loss were evaluated for MLH1 promoter hypermethylation. Results: One hundred and eighteen cases were analyzed. The overall percent agreement (OPA) for each evaluated marker status compared to next-generation sequencing (NGS) exceeded 96%. Twenty-three cases were positive for the BRAF V600E mutation by IHC and NGS, and twenty cases showed loss of MLH1 protein and were positive for MLH1 hypermethylation. Samples with loss of MMR protein expression by IHC demonstrated genetic and/or epigenetic alterations that were consistent with the observed protein expression patterns. Conclusions: The results of this study indicate that ready-to-use IHC assays can correctly identify the loss of MMR proteins and the presence of mutated BRAF V600E protein, supporting the utility of the VENTANA MMR IHC Panel as an aid to stratify patients with sporadic CRC vs. potential Lynch syndrome.

Microsatellite instability (MSI) is an emerging actionable phenotype in oncology that informs tumor response to immune checkpoint pathway immunotherapy. However, there remains a need for MSI diagnostics that are low cost, highly accurate, and generalizable across cancer types. We developed a method for targeted high-throughput sequencing of numerous microsatellite loci with pan-cancer informativity for MSI using single-molecule molecular inversion probes (smMIPs). We designed a smMIP panel targeting 111 loci highly informative for MSI across cancers. We developed an analytical framework taking advantage of smMIP-mediated error correction to specifically and sensitively detect instability events without the need for typing matched normal material. Using synthetic DNA mixtures, smMIPs were sensitive to at least 1% MSI-positive cells and were highly consistent across replicates. The fraction of identified unstable microsatellites discriminated tumors exhibiting MSI from those lacking MSI with high accuracy across colorectal (100% diagnostic sensitivity and specificity), prostate (100% diagnostic sensitivity and specificity), and endometrial cancers (95.8% diagnostic sensitivity and 100% specificity). MSI-PCR, the current standard-of-care molecular diagnostic for MSI, proved equally robust for colorectal tumors but evidenced multiple false-negative results in prostate (81.8% diagnostic sensitivity and 100% specificity) and endometrial (75.0% diagnostic sensitivity and 100% specificity) tumors. smMIP capture provides an accurate, diagnostically sensitive, and economical means to diagnose MSI across cancer types without reliance on patient-matched normal material. The assay is readily scalable to large numbers of clinical samples, enables automated and quantitative analysis of microsatellite instability, and is readily standardized across clinical laboratories.

In lung adenocarcinoma, canonical EML4-ALK inversion results in a fusion protein with a constitutively active ALK kinase domain. Evidence of ALK rearrangement occurs in a minority (2–7%) of lung adenocarcinoma, and only ~60% of these patients will respond to targeted ALK inhibition by drugs such as crizotinib and ceritinib. Clinically, targeted anti-ALK therapy is often initiated based on evidence of an ALK genomic rearrangement detected by fluorescence in situ hybridization (FISH) of interphase cells in formalin-fixed, paraffin-embedded tissue sections. At the genomic level, however, ALK rearrangements are heterogeneous, with multiple potential breakpoints in EML4, and alternate fusion partners. Using next-generation sequencing of DNA and RNA together with ALK immunohistochemistry, we comprehensively characterized genomic breakpoints in 33 FISH-positive lung adenocarcinomas. Of these 33 cases, 29 (88%) had detectable DNA level ALK rearrangements involving EML4, KIF5B, or non-canonical partners including ASXL2, ATP6V1B1, PRKAR1A, and SPDYA. A subset of 12 cases had material available for RNA-Seq. Of these, eight of eight (100%) cases with DNA rearrangements showed ALK fusion transcripts from RNA-Seq; three of four cases (75%) without detectable DNA rearrangements were similarly negative by RNA-Seq, and one case was positive by RNA-Seq but negative by DNA next-generation sequencing. By immunohistochemistry, 17 of 19 (89%) tested cases were clearly positive for ALK protein expression; the remaining cases had no detectable DNA level rearrangement or had a non-canonical rearrangement not predicted to form a fusion protein. Survival analysis of patients treated with targeted ALK inhibitors demonstrates a significant difference in mean survival between patients with next-generation sequencing confirmed EML4-ALK rearrangements, and those without (20.6 months vs 5.4 months, P<0.01). Together, these data demonstrate abundant genomic heterogeneity among ALK-rearranged lung adenocarcinoma, which may account for differences in treatment response with targeted ALK inhibitors.

BackgroundMolecular genetic diagnoses are critical to prevention and treatment of inherited polyposis and colorectal cancer. 19 genes responsible for these conditions are known, but many severely affected patients and families remain unsolved. Cryptic intronic variants that alter splicing of these genes and incomplete characterisation of recessive predisposition contribute to these diagnostic gaps.MethodsAdaptive sampling long-read DNA sequencing targeted to 19 colon cancer genes, paired with direct long-read RNA whole-transcriptome sequencing, was undertaken for four patients referred for deficiency of mismatch repair proteins and/or familial polyposis, for whom multigene panel testing yielded negative or uncertain germline results.ResultsGenetic diagnoses were obtained for all four patients. Each patient carried a cryptic intronic germline variant in a different colon cancer gene. The variants abrogated splicing by various mechanisms, all leading to loss of gene function. Patient 1 was heterozygous for intronic insertion into MSH2 of an Alu element, leading to extension of transcription into the affected intron and a stop. Patient 2 was heterozygous for deep intronic insertion into APC of a Long Interspersed Nuclear Element (LINE), creating a pseudoexon and a stop. Patient 3 was compound heterozygous at MLH3, including a cryptic intronic substitution leading to exon skipping and a stop. Patient 4 was compound heterozygous at MUTYH, including a deep intronic deletion yielding an extremely short intron and transcriptional loss of an exon encoding a critical protein domain.ConclusionPaired long-read DNA and RNA sequencing can enhance diagnostic yield through detection of cryptic intronic variants that impact cancer predisposition.

Abstract Background KRAS variant alleles may have differential biological properties which impact prognosis and therapeutic options in pancreatic ductal adenocarcinomas (PDA). Materials and Methods We retrospectively identified patients with advanced PDA who received first-line therapy and underwent blood and/or tumor genomic sequencing at the University of Washington between 2013 and 2020. We examined the incidence of KRAS mutation variants with and without co-occurring PI3K or other genomic alterations and evaluated the association of these mutations with clinicopathological characteristics and survival using a Cox proportional hazards model. Results One hundred twenty-six patients had genomic sequencing data; KRAS mutations were identified in 111 PDA and included the following variants: G12D (43)/G12V (35)/G12R (23)/other (10). PI3K pathway mutations (26% vs. 8%) and homologous recombination DNA repair (HRR) defects (35% vs. 12.5%) were more common among KRAS G12R vs. non-G12R mutated cancers. Patients with KRAS G12R vs. non-G12R cancers had significantly longer overall survival (OS) (HR 0.55) and progression-free survival (PFS) (HR 0.58), adjusted for HRR pathway co-mutations among other covariates. Within the KRAS G12R group, co-occurring PI3K pathway mutations were associated with numerically shorter OS (HR 1.58), while no effect was observed on PFS. Conclusions Patients with PDA harboring KRAS G12R vs. non-G12R mutations have longer survival, but this advantage was offset by co-occurring PI3K alterations. The KRAS/PI3K genomic profile could inform therapeutic vulnerabilities in patients with PDA. This retrospective analysis of patients with metastatic and locally advanced pancreatic ductal adenocarcinoma characterizes prognostic or predictive genomic markers for this patient population, with a focus on KRAS mutational variants and their interaction with concurrent molecular alterations.

Abstract Background The urgent need for massively scaled clinical testing for SARS-CoV-2, along with global shortages of critical reagents and supplies, has necessitated development of streamlined laboratory testing protocols. Conventional nucleic acid testing for SARS-CoV-2 involves collection of a clinical specimen with a nasopharyngeal swab in transport medium, nucleic acid extraction, and quantitative reverse-transcription PCR (RT–qPCR). As testing has scaled across the world, the global supply chain has buckled, rendering testing reagents and materials scarce. To address shortages, we developed SwabExpress, an end-to-end protocol developed to employ mass produced anterior nares swabs and bypass the requirement for transport media and nucleic acid extraction. Methods We evaluated anterior nares swabs, transported dry and eluted in low-TE buffer as a direct-to-RT–qPCR alternative to extraction-dependent viral transport media. We validated our protocol of using heat treatment for viral inactivation and added a proteinase K digestion step to reduce amplification interference. We tested this protocol across archived and prospectively collected swab specimens to fine-tune test performance. Results After optimization, SwabExpress has a low limit of detection at 2–4 molecules/µL, 100% sensitivity, and 99.4% specificity when compared side by side with a traditional RT–qPCR protocol employing extraction. On real-world specimens, SwabExpress outperforms an automated extraction system while simultaneously reducing cost and hands-on time. Conclusion SwabExpress is a simplified workflow that facilitates scaled testing for COVID-19 without sacrificing test performance. It may serve as a template for the simplification of PCR-based clinical laboratory tests, particularly in times of critical shortages during pandemics.