Development, testing and validation of a targeted NGS-panel for the detection of actionable mutations in lung cancer (NSCLC) using anchored multiplex PCR technology in a multicentric setting.

Lung cancer is a paradigm for a genetically driven tumor. A variety of drugs were developed targeting specific biomarkers requiring testing for tumor genetic alterations in relevant biomarkers. Different next-generation sequencing technologies are available for library generation: 1) anchored multiplex-, 2) amplicon based- and 3) hybrid capture-based-PCR. Anchored multiplex PCR-based sequencing was investigated for routine molecular testing within the national Network Genomic Medicine Lung Cancer (nNGM). Four centers applied the anchored multiplex ArcherDX-Variantplex nNGMv2 panel to re-analyze samples pre-tested during routine diagnostics. Data analyses were performed by each center and compiled centrally according to study design. Pre-defined standards were utilized, and panel sensitivity was determined by dilution experiments. nNGMv2 panel sequencing was successful in 98.9% of the samples (N = 90). With default filter settings, all but two potential MET exon 14 skipping variants were identified at similar allele frequencies. Both MET variants were found with an adapted calling filter. Three additional variants (KEAP1, STK11, TP53) were called that were not identified in pre-testing analyses. Only total DNA amount but not a qPCR-based DNA quality score correlated with average coverage. Analysis was successful with a DNA input as low as 6.25 ng. Anchored multiplex PCR-based sequencing (nNGMv2) and a sophisticated user-friendly Archer-Analysis pipeline is a robust and specific technology to detect tumor genetic mutations for precision medicine of lung cancer patients.

Molecular heterogeneity in histomorphologic subtypes of lung adeno carcinoma represents a challenge for treatment decision.

Lung cancer is the leading cause in cancer related death, with non-small cell lung cancer (NSCLC) being the most frequent subtype. The importance of NSCLC is reflected by the various targeted therapy options especially for NSCLC adenocarcinomas (lung adeno carcinoma (LUAD)) as well as a set of options for immune therapies. However, despite these therapy advances, the majority of patients do not show a long-term response to either targeted therapy or immune checkpoint inhibition. One reason for treatment failure appears to be the NSCLC tumor heterogeneity. NSCLC heterogeneity might lead to an insufficient molecular characterization of a given sample due to the limited tumor material used for pathological assessment as the majority of analyses is performed on small biopsies. To get a more detailed insight into the tumor heterogeneity of NSCLC LUAD, especially in the light of its different histomorphological growth patterns, we analysed isolated NSCLC growth pattern areas and the corresponding entire tumor samples of a cohort of 31 NSLCS LUAD patients and compared their mutational landscape and their expression profiles. While significant differences of complex biomarkers, like tumor mutational burden (TMB) or microsatellite instability (MSI), were not detected between the five growth patterns -lepidic, papillary, micropapillary, acinar, and solid- we observed various subclonal mutations and copy number variants. Moreover, RNASeq analysis revealed growth pattern specific expression profiles affecting cellular processes like apoptosis, metastasis and proliferation. Taken together, our data provide novel insights into the tumor heterogeneity of LUAD required to overcome tumor heterogeneity related therapy resistance.

Multicentric pilot study to standardize clinical whole exome sequencing (WES) for cancer patients.

A growing number of druggable targets and national initiatives for precision oncology necessitate broad genomic profiling for many cancer patients. Whole exome sequencing (WES) offers unbiased analysis of the entire coding sequence, segmentation-based detection of copy number alterations (CNAs), and accurate determination of complex biomarkers including tumor mutational burden (TMB), homologous recombination repair deficiency (HRD), and microsatellite instability (MSI). To assess the inter-institution variability of clinical WES, we performed a comparative pilot study between German Centers of Personalized Medicine (ZPMs) from five participating institutions. Tumor and matched normal DNA from 30 patients were analyzed using custom sequencing protocols and bioinformatic pipelines. Calling of somatic variants was highly concordant with a positive percentage agreement (PPA) between 91 and 95% and a positive predictive value (PPV) between 82 and 95% compared with a three-institution consensus and full agreement for 16 of 17 druggable targets. Explanations for deviations included low VAF or coverage, differing annotations, and different filter protocols. CNAs showed overall agreement in 76% for the genomic sequence with high wet-lab variability. Complex biomarkers correlated strongly between institutions (HRD: 0.79-1, TMB: 0.97-0.99) and all institutions agreed on microsatellite instability. This study will contribute to the development of quality control frameworks for comprehensive genomic profiling and sheds light onto parameters that require stringent standardization.

AMBAR - Interactive Alteration annotations for molecular tumor boards.

MOTIVATION: Personalized decision-making for cancer therapy relies on molecular profiling from sequencing data in combination with database evidence and expert knowledge. Molecular tumor boards (MTBs) bring together clinicians and scientists with diverse expertise and are increasingly established in the clinical routine for therapeutic interventions. However, the analysis and documentation of patients data are still time-consuming and difficult to manage for MTBs, especially as few tools are available for the amount of information required. RESULTS: To overcome these limitations, we developed an interactive web application AMBAR (Alteration annotations for Molecular tumor BoARds), for therapeutic decision-making support in MTBs. AMBAR is an R shiny-based application that allows customization, interactive filtering, visualization, adding expert knowledge, and export to clinical systems of annotated mutations. AVAILABILITY: AMBAR is dockerized, open source and available at https://sysbio.uni-ulm.de/?Software:Ambar Contact:hans.kestler@uni-ulm.de.

Heterogeneous expression of predictive biomarkers PD-L1 and TIGIT in non-mucinous lung adenocarcinoma and corresponding lymph node metastasis: A challenge for clinical biomarker testing.

The use of immune checkpoint inhibitors (ICI) targeting the PD-L1:PD1 interaction revolutionized tumor treatment by re-activating the anti-tumoral capacity of the immune system. Assessment of tumor mutational burden, microsatellite instability, or expression of the surface marker PD-L1 have been used to predict individual response to ICI therapy. However, the predicted response does not always correspond to the actual therapy outcome. We hypothesize that tumor heterogeneity might be a major cause of this inconsistency. In this respect we recently demonstrated that PD-L1 shows heterogenous expression in the different growth patterns of non-small cell lung cancer (NSCLC) - lepidic, acinar, papillary, micropapillary and solid. Furthermore, additional inhibitory receptors, like T cell immunoglobulin and ITIM domain (TIGIT), appear to be heterogeneously expressed and affect the outcome of anti-PD-L1 treatment. Given this heterogeneity in the primary tumor, we set out to analyze the situation in corresponding lymph node metastases, since these are often used to obtain biopsy material for tumor diagnosis, staging and molecular analysis. Again, we observed heterogeneous expression of PD-1, PD-L1, TIGIT, Nectin-2 and PVR in relation to different regions and growth pattern distribution that varied between the primary tumor and their metastases. Together, our study underscores the complex situation regarding the heterogeneity of NSCLC samples and suggest that the analysis of a small biopsy from lymph node metastases may not be sufficient to ensure a reliable prediction of ICI therapy success.

Targetable alterations in primary extranodal diffuse large B-cell lymphoma.

Primary extranodal diffuse large B-cell lymphoma (PE-DLBCL) is a heterogeneous subgroup of DLBCL. We investigated the prevalence and prognostic value of surface expression of PD-L1, PD1, and CD30, copy number of 9p24.1 (PD-L1 region), and mutations in MYD88, CD79B, CARD11, and BTK in a cohort of 116 patients, localized in the mediastinum (PMBL, n = 12), ear, nose and throat (ENT, n = 28), central nervous system (n = 29), testis (n = 7), breast (n = 4), stomach (n = 10), bone (n = 8), spleen (n = 2), and skin (n = 16). PD-L1 expression is most frequent in PMBL (92%), followed by lymphomas originating in the stomach (57%), ENT (23%), and skin (18%). PD1 was expressed at low levels in less than 13% of PE-DLBCL, while CD30 expression was found in 58% of PMBL. Mutation analysis revealed an unexpectedly high frequency of MYD88 and CD79B mutations in ENT lymphomas (46% and 50%, respectively). CARD11 mutations are rare but more frequently found in gastric lymphomas (30%), suggesting BTK resistance. Thirty-four of 113 (30%) of the lymphomas harbored both MYD88 and CD79B mutations. Lower overall and progression-free survival rates were found for cases with MYD88, CD79B, and BTK mutations. These data confirm the biologic singularity of PE-DLBCLs and provide some suggestions for targeted therapies.

Epigenetic lockdown of CDKN1A (p21) and CDKN2A (p16) characterises the neoplastic spindle cell component of giant cell tumours of bone.

Giant cell tumour of bone (GCTB) comprises the eponymous osteoclastic multinucleated giant cells eliciting bone lysis, an H3F3A-mutated neoplastic mononucleated fibroblast-like cell population, and H3F3A wild-type mononucleated stromal cells. In this study, we characterised four new cell lines from GCTB. Furthermore, we compared the genome-wide DNA methylation profile of 13 such tumours and three further cell lines with giant cell-rich lesions comprising three H3F3B-mutated chondroblastomas, three USP6-rearranged aneurysmal bone cysts, three non-ossifying fibromas, two hyperparathyroidism-associated brown tumours as well as mesenchymal stem cells, osteoblasts, and osteoclasts. In an unsupervised analysis, we delineated GCTB and chondroblastomas from the other analysed tumour entities. Using comparative methylation analysis, we demonstrated that the methylation pattern of the cell lines approximately equals that of H3F3A-mutated stromal cells in tissue. These patterns more resemble that of osteoblasts than that of mesenchymal stem cells, which argues for the osteoblast as the cell of origin of giant cell tumours of bone. Using enrichment analysis, we detected distinct hypermethylated clusters containing histone and collagen genes as well as target genes of the tumour suppressor p53. We found that the promotor regions of CDKN1A, CDKN2A, and IGFBP3 are methylated more strongly in GCTB than in the other giant cell-containing lesions, mesenchymal stem cells, osteoblasts, and osteoclasts (p < 0.001). This hypermethylation correlates with the lower gene expression at the mRNA level for these three genes in the cell lines, the lack of p16 and p21 in these cell lines, and the lower expression of p16 and p21 in GCTB. Overall, our analysis reveals characteristic DNA methylation patterns of giant cell tumours of bone and chondroblastomas and shows that cell lines of giant cell tumours of bone are a valid model for further analysis of H3F3A-mutated tumour cells. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

CARD9 Forms an Alternative CBM Complex in Richter Syndrome.

Richter syndrome (RS) is defined as the transformation of chronic lymphocytic leukemia (CLL) into an aggressive lymphoma, mostly diffuse large B-cell lymphoma (DLBCL). Despite intensive therapy, patients with RS have an unfavorable clinical outcome. The detailed pathobiology of Richter transformation still needs to be elucidated. Here, we report high mRNA and protein levels of CARD9 in the RS cell line U-RT1. Co-immunoprecipitation revealed the assembly of a CBM complex using CARD9 instead of CARD11. CARD9 is known to be an activator of NF-кB signaling in myeloid cells. U-RT1 Western blot analyses showed phosphorylation of IκB as well as IKK, indicating a constitutively active canonical NF-кB pathway. This was further supported by the significant reduction in cell viability and CYLD cleavage products after CARD9 siRNA knockdown. We also showed immunostaining for CARD9 in 53% of cases analyzed in a series of RS tissue specimens, whereas other lymphomas rarely show CARD9 expression. This is the first report on ectopic expression and function of CARD9 in an aggressive B-cell lymphoma. Our findings suggest that CARD9 may contribute to the pathogenesis of RS.

CCND3 is indispensable for the maintenance of B-cell acute lymphoblastic leukemia.

The D-type cyclins (CCND1, CCND2, and CCND3) in association with CDK4/6 are known drivers of cell cycle progression. We reported previously that inactivation of FOXO1 confers growth arrest and apoptosis in B-ALL, partially mediated by subsequent depletion of CCND3. Given that previously the canonical MYC target CCND2 has been considered to play the major role in B-ALL proliferation, further investigation of the role of FOXO1 in CCND3 transcription and the role of CCND3 in B-ALL is warranted. In this study, we demonstrated that CCND3 is essential for the proliferation and survival of B-ALL, independent of the mutational background. Respectively, its expression at mRNA level exceeds that of CCND1 and CCND2. Furthermore, we identified FOXO1 as a CCND3-activating transcription factor in B-ALL. By comparing the effects of CCND3 depletion and CDK4/6 inhibition by palbociclib on B-ALL cells harboring different driver mutations, we found that the anti-apoptotic effect of CCND3 is independent of the kinase activity of the CCND3-CDK4/6 complex. Moreover, we found that CCND3 contributes to CDK8 transcription, which in part might explain the anti-apoptotic effect of CCND3. Finally, we found that increased CCND3 expression is associated with the development of resistance to palbociclib. We conclude that CCND3 plays an essential role in the maintenance of B-ALL, regardless of the underlying driver mutation. Moreover, downregulation of CCND3 expression might be superior to inhibition of CDK4/6 kinase activity in terms of B-ALL treatment.

Combination of two monoclonal antibodies with SOCS1 N- and C-terminal binding sites to address SOCS1 status in B cells and B-cell lymphoma.

INTRODUCTION: Accumulating studies show that the tumour suppressor SOCS1 is one of the most frequently mutated genes in lymphomas, often affecting the coding sequence of SOCS1 protein. Depending on the type of mutation and lymphoma concerned, SOCS1 mutations have different impacts on progression-free and overall survival. Two antibodies binding the N and C terminals of SOCS1 would be a suitable 'test pair' to identify truncated versions of SOCS1. We, therefore, compared the C-terminal antibody 424C with the N-terminal antibody 4H1. MATERIALS AND METHODS: As 424C has already been characterised, we performed a comparative analysis of anti-SOCS1 antibody 4H1 using immunohistochemistry on human tonsil tissue and chamber slides, immunoblots on SOCS1 wildtype and mutated transfected HEK293T cells and lymphoma cell lines and cross-reactivity analysis and epitope mapping with protein microarrays. RESULTS: Compared with 424C, anti-SOCS1 antibody 4H1 showed various cross-reactions with other proteins resulting in a 'pancellular' immunohistochemical staining pattern in FFPE lymphoid tissue. Like 424C, 4H1 identified SOCS1 wildtype and SOCS1 mutations in immunoblot experiments but also bound an unknown protein with high intensity. CONCLUSION: Anti-SOCS1 antibody 4H1 may be useful in a molecular setting but is disqualified as an immunohistochemical diagnostic tool due to its very broad non-specific binding.

Efficacy of Immune Checkpoint Inhibitors Alone or in Combination With Chemotherapy in NSCLC Harboring ERBB2 Mutations.

INTRODUCTION: In contrast to other driver mutations, no targeted therapies have yet been approved in ERBB2-mutated NSCLC (HER2mu NSCLC). Nevertheless, several compounds have revealed promising early efficacy data, which need to be evaluated in the context of current standard approaches. Although data on the efficacy of immune checkpoint inhibitors (ICIs) in second or subsequent lines of treatment remain limited and conflicting, there are virtually no data on patient outcome under ICI/platinum-doublet combinations in the first-line setting. METHODS: We retrospectively evaluated outcomes of patients with HER2mu NSCLC treated with ICI alone or in combination with chemotherapy within the German National Network Genomic Medicine Lung Cancer consortium by means of overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). RESULTS: ICI either in combination with chemotherapy or as monotherapy was applied as first-line treatment in 27 patients, whereas 34 received single-agent ICI in second or subsequent lines. Patient characteristics were in line with previously published data. In treatment-naive patients receiving ICI in combination with chemotherapy, the ORR, median PFS, and OS rate at 1 year were 52%, 6 months, and 88%, respectively. In second or subsequent lines, ICI monotherapy was associated with an ORR of 16%, a median PFS of 4 months, and a median OS of 10 months. CONCLUSIONS: ICIs are effective as monotherapy and in combination with platinum-doublet chemotherapy. Therefore, ICI-based treatments may be found as the current standard of care and benchmark for targeted therapies in HER2mu NSCLC.

Target Heterogeneity in Oncology: The Best Predictor for Differential Response to Radioligand Therapy in Neuroendocrine Tumors and Prostate Cancer.

Tumor or target heterogeneity (TH) implies presence of variable cellular populations having different genomic characteristics within the same tumor, or in different tumor sites of the same patient. The challenge is to identify this heterogeneity, as it has emerged as the most common cause of 'treatment resistance', to current therapeutic agents. We have focused our discussion on 'Prostate Cancer' and 'Neuroendocrine Tumors', and looked at the established methods for demonstrating heterogeneity, each with its advantages and drawbacks. Also, the available theranostic radiotracers targeting PSMA and somatostatin receptors combined with targeted systemic agents, have been described. Lu-177 labeled PSMA and DOTATATE are the 'standard of care' radionuclide therapeutic tracers for management of progressive treatment-resistant prostate cancer and NET. These approved therapies have shown reasonable benefit in treatment outcome, with improvement in quality of life parameters. Various biomarkers and predictors of response to radionuclide therapies targeting TH which are currently available and those which can be explored have been elaborated in details. Imaging-based features using artificial intelligence (AI) need to be developed to further predict the presence of TH. Also, novel theranostic tools binding to newer targets on surface of cancer cell should be explored to overcome the treatment resistance to current treatment regimens.

Spatial distribution of immune checkpoint proteins in histological subtypes of lung adenocarcinoma.

The most prevalent histological type of non-small cell lung cancer (NSCLC) is adenocarcinoma. The WHO classifies this tumor into subtypes according to the predominant growth pattern such as lepidic, acinar, papillary, solid or micropapillary, each harboring specific molecular features. NSCLC adenocarcinoma heterogeneity is discussed to be a reason for therapy failure using targeted therapy or immune checkpoint inhibitors. For successful therapy of immune checkpoint inhibitors the expression and distribution of the involved immune checkpoint proteins is essential. Therefore, we aimed to investigate the distribution of five prominent immune checkpoint proteins in regard of the histological growth patterns of lung adenocarcinoma. We performed immunohistochemical staining of 84 tumor segments from 22 resected tumor samples to evaluate the expression of PD-L1, PD-1, Nectin-2, PVR, and TIGIT in distinct growth patterns of lung adenocarcinoma. We determined a distinct heterogeneity between and within different tumor segments regarding morphological growth patterns. Furthermore, expression of immune checkpoint proteins varied between different growth pattern areas as well as within one distinct growth pattern. Expression of PVR was significantly higher in solid compared to acinar growth pattern (p= 0.00736). Of note, we detected TIGIT not only on tumor infiltrating lymphocytes but also on tumor cells, whereas non-neoplastic lung tissue was consistently TIGIT-negative. The immune checkpoint protein distribution in histologic subtypes of pulmonary adenocarcinoma displays an considerable intra- and intertumoral heterogeneity implying the requirement of either a multiregion or an adjusted analysis when determining the expression status of PD-1:PD-L1 and the TIGIT:PVR/Nectin-2 checkpoint proteins as predictive markers.

Age-related activity of Poly (ADP-Ribose) Polymerase (PARP) in men with localized prostate cancer.

Mutations in DNA repair genes have been connected with familial prostate cancer and sensitivity to targeted drugs like PARP-inhibitors. Clinical use of this information is limited by the small fraction of prostate cancer risk gene carriers, variants of unknown pathogenicity and the focus on monogenic disease mechanisms. Functional assays capturing mono- and polygenic defects were shown to detect breast and ovarian cancer risk in blood-derived cells. Here, we comparatively analyzed lymphocytes from prostate cancer patients and controls applying a sensitive DNA double-strand break (DSB) repair assay and a flow cytometrybased assay measuring the activity of Poly(ADP-Ribose)-Polymerase, a target in treatment of metastatic prostate cancer. Contrary to breast and ovarian cancer patients, error-prone DNA double-strand break repair was not activated in prostate cancer patients. Yet, the activity of PARP discriminated between prostate cancer cases and controls. PARylation also correlated with the age of male probands, suggesting male-specific links between mutation-based and aging-associated DNA damage accumulation and PARP. Our work identifies prostate cancer-specific DNA repair phenotypes characterized by increased PARP activities and carboplatin-sensitivities, detected by functional testing of lymphocytes. This provides new insights for further investigation of PARP and carboplatin sensitivity as biomarkers in peripheral cells of men and prostate cancer patients.

Increasing Mean Age of Head and Neck Cancer Patients at a German Tertiary Referral Center.

BACKGROUND: The impact of demographic change on the age at diagnosis in German head and neck cancer (HNC) patients is unclear. Here we present an evaluation of aging trends in HNC at a tertiary referral center. METHODS: Retrospective cohort study on aging trends at the initial diagnosis of newly diagnosed patients with HNC between 2004 and 2018 at the head and neck cancer center Ulm in relation to demographic data of the catchment area. RESULTS: The study population consisted of 2450 individuals diagnosed with HNC with a mean age of 62.84 (±11.67) years. We observed a significant increase in annual incidence rates and mean age over time. Mean age among HNC patients increased significantly more than among the population in the catchment area. Whereas the incidence rate of patients <50 years did not change, the incidence of HNC patients aged ≥70 years increased the most. The mean patient age in the main tumor sites increased significantly. Surprisingly, HPV-positive patients were not younger than HPV-negative patients, but showed a non-significant trend towards a higher mean age (63.0 vs. 60.7 years). CONCLUSIONS: Increasing incidence rates in older patients pose a challenge for health care systems. A nationwide study is needed to assess the dynamics and impact of aging on the incidence of HNC.

Profiling of three H3F3A-mutated and denosumab-treated giant cell tumors of bone points to diverging pathways during progression and malignant transformation.

Giant cell tumor of bone (GCTB) is a locally aggressive lesion of intermediate malignancy. Malignant transformation of GCTB is a rare event. In 2013, the humanized monoclonal antibody against receptor activator of nuclear factor-κb-Ligand (RANKL) denosumab was approved for treatment of advanced GCTB. Since then, several reports have questioned the role of denosumab during occasional malignant transformation of GCTB. We report on three patients with H3F3A-mutated GCTBs, treated with denosumab. The tissue samples were analysed by histomorphology, immunohistochemistry, and in two instances by next generation panel sequencing of samples before and after treatment. One patient had a mutation of ARID2 in the recurrence of the GCTB under treatment with denosumab. One patient developed a pleomorphic sarcoma and one an osteoblastic osteosarcoma during treatment. Sequencing revealed a persisting H3F3A mutation in the osteosarcoma while the pleomorphic sarcoma lost the H3F3A mutation; however, a FGFR1 mutation, both in the recurrence and in the pleomorphic sarcoma persisted. In addition, the pleomorphic sarcoma showed an AKT2 and a NRAS mutation. These data are inconclusive concerning the role denosumab plays in the event of malignant progression/transformation of GCTB and point to diverging pathways of tumor progression of GCTB associated with this treatment.

A new reliable and highly specific monoclonal antibody to detect the C-terminal region of silencer of cytokine signaling 1.

INTRODUCTION: SOCS1, a negative regulator of JAK/STAT signaling, is among the most frequently mutated genes in DLBCL and classical Hodgkin lymphoma. The C-terminal SOCS box domain, mediating the degradation of phospho-JAK2, is often affected or even lacking. The analysis of such variants is hampered by the lack of a SOCS1-specific monoclonal antibody recognizing the C-terminus of SOCS1. As this C-terminus is often lost or mutated in B-cell lymphomas, staining with amino-terminal targeting antibodies in a lymphoma setting might be misleading. METHODS: BALB/c mice were immunized with a truncated SOCS1 C-terminal protein. The supernatant of generated hybridoma cells was screened by ELISA and, immunohistochemically, on formalin-fixed and paraffin-embedded tonsil. After antibody purification by affinity chromatography, epitope mapping and cross-reactivity check followed via substitution scans. SOCS1 protein expression was investigated on cell cultures and cytoblocks of SOCS1WT stably transfected HEK293T cells, lymphoma cell lines and lymphoid tissues. RESULTS: Procedures resulted in one monoclonal IgG1 anti-SOCS1 antibody, 424C, that recognizes and strongly binds to the C-terminal region of SOCS1 in immunoblot and immunohistochemistry analyses. CONCLUSION: This new anti-SOCS1 monoclonal antibody is a valuable tool to detect SOCS1 expression dependent on an existing SOCS1 box and, therefore, indicating a full-length SOCS1 protein.

The PTP1B mutant PTP1B∆2-4 is a positive regulator of the JAK/STAT signalling pathway in Hodgkin lymphoma.

The neoplastic Hodgkin/Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) depend on chronic activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathways to maintain survival and proliferation. Accumulating reports highlight the importance of the inactivation or reduced expression of negative JAK/STAT regulators such as the protein-tyrosine phosphatase 1B (PTP1B/PTPN1) in this process. Various PTPN1 mRNA variants as well as truncated PTP1B proteins were identified in cHL cell lines and primary cHL tumour samples. These PTPN1 mRNA variants lack either one or several exon sequences and therefore render these PTP1B variants catalytically inactive. Here, we show that one of these mutants, PTP1B∆2-4, is not only a catalytically inactive variant, but also augmented the IL-4-induced JAK/STAT activity similar to the recently reported PTP1B∆6 splice variant. Moreover, while PTP1B∆6 diminished the activity and protein levels of PTP1BWT, PTP1BWT remained unaffected by PTP1B∆2-4, arguing for different molecular mechanisms of JAK/STAT modulation by PTP1B∆6 and PTP1B∆2-4. Collectively, these data indicate that PTPN1 variants missing one or more exon sequences originated either from alternative splicing or from gene mutation, create PTP1B gain-of-function variants with oncogenic potential by augmenting JAK/STAT signalling in cHL.

Rescue of Non-Informative Circulating Tumor DNA to Monitor the Mutational Landscape in NSCLC.

In non-small cell lung cancer (NSCLC) the usage of plasma-derived circulating tumor DNA (ctDNA) have come into focus to obtain a comprehensive genetic profile of a given lung cancer. Despite the usage of specific sampling tubes, archived plasma samples as well as inappropriately treated blood samples still cause a loss of information due to cell lysis and contamination with cellular DNA. Our aim was to establish a reliable protocol to rescue ctDNA from such non-informative samples to monitor the mutational landscape in NSCLC. As a proof-of-concept study we used archived plasma samples derived from whole blood EDTA samples of 51 patients suffering from NSCLC. Analysis of the isolated plasma DNA determined only a small fraction of ctDNA in a range of 90-250 bp. By applying a specific purification procedure, we were able to increase the informative ctDNA content and improve in a cohort of 42 patients the detection of driver mutations from 32% to 79% of the mutations found in tissue biopsies. Thus, we present here an easy to perform, time and cost effective procedure to rescue non-informative ctDNA samples, which is sufficient to detect oncogenic mutations in NGS approaches and is therefore a valuable technical improvement for laboratories handling liquid biopsy samples.

Pancreatic cancer-derived organoids - a disease modeling tool to predict drug response.

BACKGROUND: Organotypic cultures derived from pancreatic ductal adenocarcinoma (PDAC) termed pancreatic ductal cancer organoids (PDOs) recapitulate the primary cancer and can be derived from primary or metastatic biopsies. Although isolation and culture of patient-derived pancreatic organoids were established several years ago, pros and cons for individualized medicine have not been comprehensively investigated to date. METHODS: We conducted a feasibility study, systematically comparing head-to-head patient-derived xenograft tumor (PDX) and PDX-derived organoids by rigorous immunohistochemical and molecular characterization. Subsequently, a drug testing platform was set up and validated in vivo. Patient-derived organoids were investigated as well. RESULTS: First, PDOs faithfully recapitulated the morphology and marker protein expression patterns of the PDXs. Second, quantitative proteomes from the PDX as well as from corresponding organoid cultures showed high concordance. Third, genomic alterations, as assessed by array-based comparative genomic hybridization, revealed similar results in both groups. Fourth, we established a small-scale pharmacotyping platform adjusted to operate in parallel considering potential obstacles such as culture conditions, timing, drug dosing, and interpretation of the results. In vitro predictions were successfully validated in an in vivo xenograft trial. Translational proof-of-concept is exemplified in a patient with PDAC receiving palliative chemotherapy. CONCLUSION: Small-scale drug screening in organoids appears to be a feasible, robust and easy-to-handle disease modeling method to allow response predictions in parallel to daily clinical routine. Therefore, our fast and cost-efficient assay is a reasonable approach in a predictive clinical setting.