The Efficacy Comparison of Endoscopic Bariatric Therapies: 6-Month Versus 12-Month Intragastric Balloon Versus Endoscopic Sleeve Gastroplasty.

INTRODUCTION: Intragastric balloon (IGB) insertion and endoscopic sleeve gastroplasty (ESG) are known to be effective and safe in achieving weight loss. The aim of this study was to compare the effects of a 6-month IGB therapy, a 12-month IGB therapy, and ESG. METHODS: We retrospectively analyzed the weight loss at IGB (Orbera) removal after 6 months (124 patients), at IGB (Orbera365) removal after 12 months (61 patients) and at 6 and 12 months after ESG (42 and 34 patients, respectively). Postprocedural care, including medication and diet, was the same for all procedures. RESULTS: Mean TBWL in patients undergoing IGB placement for 6 and 12 months and ESG after 6 and 12 months were 15.2, 15.8, 26.5, and 28.7 kg, respectively. There was no significant difference in the mean %TBWL in patients undergoing IGB placement for 6 or for 12 months (15.3% vs. 14.7%, P = 0.7). ESG patients showed a significantly higher mean %TBWL than IGB patients after 6 months (15.3 vs. 19.8, P = 0.005) and 12 months (14.7 vs. 22.5, P < 0.001). CONCLUSION: All three studied methods were effective for achieving weight loss. However, there was no significant difference between 6-month and 12-month IGB therapies outcomes. ESG appeared to be a more effective obesity treatment modality than IGB.

Imaging of the medial collateral ligament of the knee: a systematic review.

INTRODUCTION: The primary aim of this investigation was to systematically review relevant literature of various imaging modalities (magnetic resonance imaging (MRI), stress radiography and ultrasonography) in the assessment of patients with a medial collateral ligament (MCL) injury. MATERIALS AND METHODS: A systematic literature review of articles indexed in PubMed and Cochrane library was performed. Original research reporting data associated with medial gapping, surgical, and clinical findings associated with MCL injuries were considered for inclusion. The methodological quality of each inclusion was also assessed using a verified tool. RESULTS: Twenty-three imaging studies (magnetic resonance imaging (MRI) n = 14; ultrasonography n = 6; radiography n = 3) were ultimately included into the review. A total of 808 injured, and 294 control, knees were assessed. Interobserver reliabilities were reported in radiographic and ultrasonographic investigations with almost perfect agreement. MRI studies demonstrated agreement ranging between substantial to almost perfect. Intraobserver reliability was only reported in radiographic studies pertinent to medial gapping and was found to be almost perfect. Correlation of MRI with clinical findings was moderate to strong (65-92%). Additionally, MRI imaging was more sensitive in the detection of MCL lesions when compared to clinical examination. However, when compared to surgical findings, MRI underestimated the grade of instability in up to 21% of cases. Furthermore, MRI showed relatively inferior performance in the identification of the exact MCL-lesion location when compared to surgical findings. Interestingly, preoperative clinical examination was slightly inferior to stress radiography in the detection of MCL lesions. However, clinical testing under general anaesthesia performed similar to stress radiography. The methodological quality analysis showed a low risk of bias regarding patient selection and index testing in each imaging modality. CONCLUSION: MRI can reliably diagnose an MCL lesion but demonstrates limitations in its ability to predict the specific lesion location or grade of MCL instability. Ultrasonography is a widely available, radiation free modality, but is rarely used in clinical practice for detecting MCL lesions and clinical or surgical correlates are scarce. Stress radiography findings correlate with surgical findings but clinical correlations are missing in the literature. LEVEL OF EVIDENCE: IV.

The Use of Mobile Applications for the Diagnosis and Treatment of Tumors in Orthopaedic Oncology - a Systematic Review.

The use of smartphone apps is an essential part of everyday life. Mobile applications offer enormous opportunities for dealing with challenges in public health, and their number increases every day. This paper aims to review the existing literature on mobile applications in orthopaedic oncology and to summarize the current mobile applications for musculoskeletal tumors. A systematic literature review was conducted regarding articles on mobile applications in orthopaedic and trauma surgery. The focus was on identifying mobile applications that can be used in the treatment of patients with musculoskeletal tumors. Two reviewers independently assessed study eligibility, extracted data, and appraised methodological quality. In addition, the Apple App Store and Google Play Store were searched for suitable mobile applications. Ninety-one articles describing a mobile application in orthopaedic and trauma surgery were identified. Three articles focused on a mobile application for musculoskeletal tumors. Additionally, seven mobile applications were available in the App/Play Stores dealing with bone or soft tissue tumors in orthopaedic oncology without corresponding scientific articles. Increasing numbers of mobile applications are being developed in orthopaedic and trauma surgery. Currently, only three scientific articles on mobile applications in orthopaedic oncology are present, yet several more applications are available without scientific medical evaluation. Since mobile applications can facilitate the everyday life of orthopaedic and trauma surgeons, it is worthwhile to be aware of new developments in this field. A regular scientific evaluation of the subject is important in order to classify the significance of these applications.

Drug-induced inhibition of phosphorylation of STAT5 overrides drug resistance in neoplastic mast cells.

Systemic mastocytosis (SM) is a mast cell (MC) neoplasm with complex pathology and a variable clinical course. In aggressive SM (ASM) and MC leukemia (MCL), responses to conventional drugs are poor and the prognosis is dismal. R763 is a multi-kinase inhibitor that blocks the activity of Aurora-kinase-A/B, ABL1, AKT and FLT3. We examined the effects of R763 on proliferation and survival of neoplastic MC. R763 produced dose-dependent inhibition of proliferation in the human MC lines HMC-1.1 (IC50 5-50 nM), HMC-1.2 (IC50 1-10 nM), ROSAKIT WT (IC50 1-10 nM), ROSAKIT D816V (IC50 50-500 nM) and MCPV-1.1 (IC50 100-1000 nM). Moreover, R763 induced growth inhibition in primary neoplastic MC in patients with ASM and MCL. Growth-inhibitory effects of R763 were accompanied by signs of apoptosis and a G2/M cell cycle arrest. R763 also inhibited phosphorylation of KIT, BTK, AKT and STAT5 in neoplastic MC. The most sensitive target appeared to be STAT5. In fact, tyrosine phosphorylation of STAT5 was inhibited by R763 at 10 nM. At this low concentration, R763 produced synergistic growth-inhibitory effects on neoplastic MC when combined with midostaurin or dasatinib. Together, R763 is a novel promising multi-kinase inhibitor that blocks STAT5 activation and thereby overrides drug-resistance in neoplastic MC.

Midostaurin: a magic bullet that blocks mast cell expansion and activation.

Clinically relevant features in patients with systemic mastocytosis (SM) include the cosmetic burden of lesional skin, mediator-related symptoms, and organ damage resulting from mast cell (MC) infiltration in advanced forms of SM. Regardless of the SM variant, expansion of neoplastic MC in the skin and other organs is triggered by mutant forms of KIT, the most prevalent being D816V. Activation of MC with subsequent release of chemical mediators is often caused by IgE-dependent mechanisms in these patients. Midostaurin, also known as PKC412, blocks the kinase activity of wild-type KIT and KIT D816V, counteracts KIT-dependent growth of neoplastic MC, and inhibits IgE-dependent mediator secretion. Based on this activity-profile, the drug has been used for treatment of patients with advanced SM. Indeed, encouraging results have been obtained with the drug in a recent multi-center phase II trial in patients with advanced SM, with an overall response rate of 60% and a substantial decrease in the burden of neoplastic MC in various organs. Moreover, midostaurin improved the overall survival and relapse-free survival in patients with advanced SM compared with historical controls. In addition, midostaurin was found to improve mediator-related symptoms and quality of life, suggesting that the drug may also be useful in patients with indolent SM suffering from mediator-related symptoms resistant to conventional therapies or those with MC activation syndromes. Ongoing and future studies will determine the actual value of midostaurin-induced MC depletion and MC deactivation in these additional indications.

Proposed diagnostic criteria and classification of basophilic leukemias and related disorders.

Basophils form a distinct cell lineage within the hematopoietic cell family. In various myeloid neoplasms, including chronic myeloid leukemia, basophilia is frequently seen. Acute and chronic basophilic leukemias, albeit rare, have also been described. However, no generally accepted criteria and classification of basophilic leukemias have been presented to date. To address this unmet need, a series of Working Conferences and other meetings were organized between March 2015 and March 2016. The current article provides a summary of consensus statements from these meetings, together with proposed criteria to delineate acute basophilic leukemia (ABL) from chronic basophilic leukemia (CBL) and primary forms of the disease where no preceding myeloid malignancy is detected, from the more common 'secondary' variants. Moreover, the term hyperbasophilia (HB) is proposed for cases with a persistent peripheral basophil count ⩾1000 per µl of blood. This condition, HB, is highly indicative of the presence of an underlying myeloid neoplasm. Therefore, HB is an important checkpoint in the diagnostic algorithm and requires a detailed hematologic investigation. In these patients, an underlying myeloid malignancy is often found and is then labeled with the appendix -baso, whereas primary cases of ABL or CBL are very rare. The criteria and classification proposed in this article should facilitate the diagnosis and management of patients with unexplained basophilia and basophil neoplasms in routine practice, and in clinical studies.

Pomalidomide in myeloproliferative neoplasm-associated myelofibrosis.

Myeloproliferative neoplasm (MPN)-associated myelofibrosis is a MPN characterized by bone marrow fibrosis, cytopenias, splenomegaly and constitutional symptoms. Pomalidomide, an immune-modifying drug, is reported to improve anaemia and thrombocytopenia in some patients with MPN-associated myelofibrosis. We designed a phase 2 study of pomalidomide in patients with MPN-associated myelofibrosis and anaemia and/or thrombocytopenia and/or neutropenia. Subjects received pomalidomide 2.0 mg/day in cohort 1 (n=38) or 0.5 mg/day in cohort 2 (n=58). Prednisolone was added if there was no response after 3 months in cohort 1 and based on up-front randomization in cohort 2 if there was no response at 3 or 6 months. Response rates were 39% (95% confidence interval (CI), 26-55%) in cohort 1 and 24% (95% CI, 15-37%) in cohort 2. In a multivariable logistic regression model pomalidomide at 2.0 mg/day (odds ratio (OR), 2.62; 95% CI, 1.00-6.87; P=0.05) and mutated TET2 (OR, 5.07; 95% CI, 1.16-22.17; P=0.03) were significantly associated with responses. Median duration of responses was 13.0 months (range 0.9-52.7). There was no significant difference in response rates or duration in subjects receiving or not receiving prednisolone. Clinical trial MPNSG 01-09 is registered at ClinicalTrials.gov (NCT00949364) and clinicaltrialsregister.eu (EudraCT Number: 2009-010738-23).

Analysis of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK)-reactive CD8(+) T cell responses in children with NPM-ALK(+) anaplastic large cell lymphoma.

Cellular immune responses against the oncoantigen anaplastic lymphoma kinase (ALK) in patients with ALK-positive anaplastic large cell lymphoma (ALCL) have been detected using peptide-based approaches in individuals preselected for human leucocyte antigen (HLA)-A*02:01. In this study, we aimed to evaluate nucleophosmin (NPM)-ALK-specific CD8(+) T cell responses in ALCL patients ensuring endogenous peptide processing of ALK antigens and avoiding HLA preselection. We also examined the HLA class I restriction of ALK-specific CD8(+) T cells. Autologous dendritic cells (DCs) transfected with in-vitro-transcribed RNA (IVT-RNA) encoding NPM-ALK were used as antigen-presenting cells for T cell stimulation. Responder T lymphocytes were tested in interferon-gamma enzyme-linked immunospot (ELISPOT) assays with NPM-ALK-transfected autologous DCs as well as CV-1 in Origin with SV40 genes (COS-7) cells co-transfected with genes encoding the patients' HLA class I alleles and with NPM-ALK encoding cDNA to verify responses and define the HLA restrictions of specific T cell responses. NPM-ALK-specific CD8(+) T cell responses were detected in three of five ALK-positive ALCL patients tested between 1 and 13 years after diagnosis. The three patients had also maintained anti-ALK antibody responses. No reactivity was detected in samples from five healthy donors. The NPM-ALK-specific CD8(+) T cell responses were restricted by HLA-C-alleles (C*06:02 and C*12:02) in all three cases. This approach allowed for the detection of NPM-ALK-reactive T cells, irrespective of the individual HLA status, up to 9 years after ALCL diagnosis.

Splenomegaly, elevated alkaline phosphatase and mutations in the SRSF2/ASXL1/RUNX1 gene panel are strong adverse prognostic markers in patients with systemic mastocytosis.

We evaluated the impact of clinical and molecular characteristics on overall survival (OS) in 108 patients with indolent (n=41) and advanced systemic mastocytosis (SM) (advSM, n=67). Organomegaly was measured by magnetic resonance imaging-based volumetry of the liver and spleen. In multivariate analysis of all patients, an increased spleen volume ⩾450 ml (hazard ratio (HR), 5.2; 95% confidence interval (CI), (2.1-13.0); P=0.003) and an elevated alkaline phosphatase (AP; HR 5.0 (1.1-22.2); P=0.02) were associated with adverse OS. The 3-year OS was 100, 77, and 39%, respectively (P<0.0001), for patients with 0 (low risk, n=37), 1 (intermediate risk, n=32) or 2 (high risk, n=39) parameters. For advSM patients with fully available clinical and molecular data (n=60), univariate analysis identified splenomegaly ⩾1200 ml, elevated AP and mutations in the SRSF2/ASXL1/RUNX1 (S/A/R) gene panel as significant prognostic markers. In multivariate analysis, mutations in S/A/R (HR 3.2 (1.1-9.6); P=0.01) and elevated AP (HR 2.6 (1.0-7.1); P=0.03) remained predictive adverse prognostic markers for OS. The 3-year OS was 76 and 38%, respectively (P=0.0003), for patients with 0-1 (intermediate risk, n=28) or 2 (high risk, n=32) parameters. We conclude that splenomegaly, elevated AP and mutations in the S/A/R gene panel are independent of the World Health Organization classification and provide the most relevant prognostic information in SM patients.

Additional mutations in SRSF2, ASXL1 and/or RUNX1 identify a high-risk group of patients with KIT D816V(+) advanced systemic mastocytosis.

Most patients with KIT D816V(+) advanced systemic mastocytosis (SM) are characterized by somatic mutations in additional genes. We sought to clarify the prognostic impact of such mutations. Genotype and clinical characteristics of 70 multi-mutated KIT D816V(+) advanced SM patients were included in univariate and multivariate analyses. The most frequently identified mutated genes were TET2 (n=33 of 70 patients), SRSF2 (n=30), ASXL1 (n=20), RUNX1 (n=16) and JAK2 (n=11). In univariate analysis, overall survival (OS) was adversely influenced by mutations in SRSF2 (P<0.0001), ASXL1 (P=0.002) and RUNX1 (P=0.03), but was not influenced by mutations in TET2 or JAK2. In multivariate analysis, SRSF2 and ASXL1 remained the most predictive adverse indicators concerning OS. Furthermore, we found that inferior OS and adverse clinical characteristics were significantly influenced by the number of mutated genes in the SRSF2/ASXL1/RUNX1 (S/A/R) panel (P<0.0001). In conclusion, the presence and number of mutated genes within the S/A/R panel are adversely associated with advanced disease and poor survival in KIT D816V(+) SM. On the basis of these findings, inclusion of molecular markers should be considered in upcoming prognostic scoring systems for patients with SM.

Target interaction profiling of midostaurin and its metabolites in neoplastic mast cells predicts distinct effects on activation and growth.

Proteomic-based drug testing is an emerging approach to establish the clinical value and anti-neoplastic potential of multikinase inhibitors. The multikinase inhibitor midostaurin (PKC412) is a promising new agent used to treat patients with advanced systemic mastocytosis (SM). We examined the target interaction profiles and the mast cell (MC)-targeting effects of two pharmacologically relevant midostaurin metabolites, CGP52421 and CGP62221. All three compounds, midostaurin and the two metabolites, suppressed IgE-dependent histamine secretion in basophils and MC with reasonable IC(50) values. Midostaurin and CGP62221 also produced growth inhibition and dephosphorylation of KIT in the MC leukemia cell line HMC-1.2, whereas the second metabolite, CGP52421, which accumulates in vivo, showed no substantial effects. Chemical proteomic profiling and drug competition experiments revealed that midostaurin interacts with KIT and several additional kinase targets. The key downstream regulator FES was recognized by midostaurin and CGP62221, but not by CGP52421 in MC lysates, whereas the IgE receptor downstream target SYK was recognized by both metabolites. Together, our data show that the clinically relevant midostaurin metabolite CGP52421 inhibits IgE-dependent histamine release, but is a weak inhibitor of MC proliferation, which may have clinical implications and may explain why mediator-related symptoms improve in SM patients even when disease progression occurs.

Endoscopic-CT: Learning-Based Photometric Reconstruction for Endoscopic Sinus Surgery.

In this work we present a method for dense reconstruction of anatomical structures using white light endoscopic imagery based on a learning process that estimates a mapping between light reflectance and surface geometry. Our method is unique in that few unrealistic assumptions are considered (i.e., we do not assume a Lambertian reflectance model nor do we assume a point light source) and we learn a model on a per-patient basis, thus increasing the accuracy and extensibility to different endoscopic sequences. The proposed method assumes accurate video-CT registration through a combination of Structure-from-Motion (SfM) and Trimmed-ICP, and then uses the registered 3D structure and motion to generate training data with which to learn a multivariate regression of observed pixel values to known 3D surface geometry. We demonstrate with a non-linear regression technique using a neural network towards estimating depth images and surface normal maps, resulting in high-resolution spatial 3D reconstructions to an average error of 0.53mm (on the low side, when anatomy matches the CT precisely) to 1.12mm (on the high side, when the presence of liquids causes scene geometry that is not present in the CT for evaluation). Our results are exhibited on patient data and validated with associated CT scans. In total, we processed 206 total endoscopic images from patient data, where each image yields approximately 1 million reconstructed 3D points per image.

Lateral prefrontal model-based signatures are reduced in healthy individuals with high trait impulsivity.

High impulsivity is an important risk factor for addiction with evidence from endophenotype studies. In addiction, behavioral control is shifted toward the habitual end. Habitual control can be described by retrospective updating of reward expectations in 'model-free' temporal-difference algorithms. Goal-directed control relies on the prospective consideration of actions and their outcomes, which can be captured by forward-planning 'model-based' algorithms. So far, no studies have examined behavioral and neural signatures of model-free and model-based control in healthy high-impulsive individuals. Fifty healthy participants were drawn from the upper and lower ends of 452 individuals, completing the Barratt Impulsiveness Scale. All participants performed a sequential decision-making task during functional magnetic resonance imaging (fMRI) and underwent structural MRI. Behavioral and fMRI data were analyzed by means of computational algorithms reflecting model-free and model-based control. Both groups did not differ regarding the balance of model-free and model-based control, but high-impulsive individuals showed a subtle but significant accentuation of model-free control alone. Right lateral prefrontal model-based signatures were reduced in high-impulsive individuals. Effects of smoking, drinking, general cognition or gray matter density did not account for the findings. Irrespectively of impulsivity, gray matter density in the left dorsolateral prefrontal cortex was positively associated with model-based control. The present study supports the idea that high levels of impulsivity are accompanied by behavioral and neural signatures in favor of model-free behavioral control. Behavioral results in healthy high-impulsive individuals were qualitatively different to findings in patients with the same task. The predictive relevance of these results remains an important target for future longitudinal studies.

Identification of bromodomain-containing protein-4 as a novel marker and epigenetic target in mast cell leukemia.

Advanced systemic mastocytosis (SM) is a life-threatening neoplasm characterized by uncontrolled growth and accumulation of neoplastic mast cells (MCs) in various organs and a poor survival. So far, no curative treatment concept has been developed for these patients. We identified the epigenetic reader bromodomain-containing protein-4 (BRD4) as novel drug target in aggressive SM (ASM) and MC leukemia (MCL). As assessed by immunohistochemistry and PCR, neoplastic MCs expressed substantial amounts of BRD4 in ASM and MCL. The human MCL lines HMC-1 and ROSA also expressed BRD4, and their proliferation was blocked by a BRD4-specific short hairpin RNA. Correspondingly, the BRD4-targeting drug JQ1 induced dose-dependent growth inhibition and apoptosis in HMC-1 and ROSA cells, regardless of the presence or absence of KIT D816V. In addition, JQ1 suppressed the proliferation of primary neoplastic MCs obtained from patients with ASM or MCL (IC50: 100-500 nm). In drug combination experiments, midostaurin (PKC412) and all-trans retinoic acid were found to cooperate with JQ1 in producing synergistic effects on survival in HMC-1 and ROSA cells. Taken together, we have identified BRD4 as a promising drug target in advanced SM. Whether JQ1 or other BET-bromodomain inhibitors are effective in vivo in patients with advanced SM remains to be elucidated.

Benign and Malignant Proliferative Fibro-osseous and Osseous Lesions of the Oral Cavity of Dogs.

Ossifying fibroma (OF) and fibrous dysplasia (FD) are benign, intraosseous, proliferative fibro-osseous lesions (PFOLs) characterized by replacement of normal bone by a fibrous matrix with various degrees of mineralization and ossification. Osteomas are benign tumors composed of mature, well-differentiated bone. Clinical, imaging, and histologic features of 15 initially diagnosed benign PFOLs and osteomas of the canine oral cavity were evaluated. Final diagnoses after reevaluation were as follows: OF (3 cases), FD (4 cases), low-grade osteosarcoma (LG-OSA) (3 cases), and osteoma (5 cases). Histology alone often did not result in a definitive diagnosis for PFOL. OF appeared as a well-circumscribed, radiopaque mass with some degree of bone lysis on imaging. Most lesions of FD showed soft tissue opacity with bone lysis and ill-defined margins. Low-grade OSA appeared as a lytic lesion with a mixed opacity and ill-defined margins. Osteomas were characterized by a mineralized, expansile, well-circumscribed lesion. Although histologic features of PFOLs were typically bland, the lesions diagnosed as LG-OSA had some features of malignancy (eg, bone invasion or a higher mitotic index). Treatment varied widely. Of the 10 dogs with benign PFOL or osteoma with known outcome (10/12), 9 showed either complete response (6/10) or stable disease (3/10) after treatment. Of the 2 dogs with LG-OSA with known outcome, 1 showed complete response after curative intent surgery, but 1 patient had recurrence after partial maxillectomy. Definitive diagnosis of mandibular/maxillary PFOL is challenging via histopathologic examination alone, and accurate diagnosis is best achieved through assimilation of clinical, imaging, and histopathologic features.

Rendering-Based Video-CT Registration with Physical Constraints for Image-Guided Endoscopic Sinus Surgery.

We present a system for registering the coordinate frame of an endoscope to pre- or intra- operatively acquired CT data based on optimizing the similarity metric between an endoscopic image and an image predicted via rendering of CT. Our method is robust and semi-automatic because it takes account of physical constraints, specifically, collisions between the endoscope and the anatomy, to initialize and constrain the search. The proposed optimization method is based on a stochastic optimization algorithm that evaluates a large number of similarity metric functions in parallel on a graphics processing unit. Images from a cadaver and a patient were used for evaluation. The registration error was 0.83 mm and 1.97 mm for cadaver and patient images respectively. The average registration time for 60 trials was 4.4 seconds. The patient study demonstrated robustness of the proposed algorithm against a moderate anatomical deformation.

F604S exchange in FIP1L1-PDGFRA enhances FIP1L1-PDGFRA protein stability via SHP-2 and SRC: a novel mode of kinase inhibitor resistance.

FIP1L1-PDGFRA is a constitutively activated kinase described in chronic eosinophilic leukemia (CEL) and hypereosinophilic syndrome (HES). Imatinib is clinically active in FIP1L1-PDGFRA-positive diseases. Using in vitro screening to identify imatinib-resistant mutations, we frequently detected a Phe to Ser exchange at position 604 (F604S) of FIP1L1-PDGFRA alone or in combination with other exchanges. Surprisingly, FIP1L1-PDGFRA/F604S did not increase the biochemical or cellular IC50 value of imatinib when compared with unmutated FIP1L1-PDGFRA. However, FIP1L1-PDGFRA/F604S more efficiently induced growth factor independence in cell lines and primary mouse bone marrow cells. Pulse chase analysis revealed that the F604S exchange strongly stabilized FIP1L1-PDGFRA/F604S. The F604S mutation creates a binding site for the phosphatase domain of SHP-2, leading to lower autophosphorylation of FIP1L1-PDGFRA/F604S. This is associated with a reduced activation of SRC and CBL by FIP1L1-PDGFRA/F604S compared with the unmutated oncogene. As SRC inhibition and knockdown resulted in FIP1L1-PDGFRA stabilization, this explains the extended half-life of FIP1L1-PDGFRA/F604S. Interestingly, FIP1L1-PDGFRA/L629P, a recently identified mutation in an imatinib-resistant CEL patient, also showed protein stabilization similar to that observed with FIP1L1-PDGFRA/F604S. Therefore, resistance mutations in FIP1L1-PDGFRA that do not interfere with drug binding but rather increase target protein stability seem to be one of the drug-resistance mechanisms in FIP1L1-PDGFRA-positive disease.

KIT mutation analysis in mast cell neoplasms: recommendations of the European Competence Network on Mastocytosis.

Although acquired mutations in KIT are commonly detected in various categories of mastocytosis, the methodologies applied to detect and quantify the mutant type and allele burden in various cells and tissues are poorly defined. We here propose a consensus on methodologies used to detect KIT mutations in patients with mastocytosis at diagnosis and during follow-up with sufficient precision and sensitivity in daily practice. In addition, we provide recommendations for sampling and storage of diagnostic material as well as a robust diagnostic algorithm. Using highly sensitive assays, KIT D816V can be detected in peripheral blood leukocytes from most patients with systemic mastocytosis (SM) that is a major step forward in screening and SM diagnosis. In addition, the KIT D816V allele burden can be followed quantitatively during the natural course or during therapy. Our recommendations should greatly facilitate diagnostic and follow-up investigations in SM in daily practice as well as in clinical trials. In addition, the new tools and algorithms proposed should lead to a more effective screen, early diagnosis of SM and help to avoid unnecessary referrals.

Molecular profiling of myeloid progenitor cells in multi-mutated advanced systemic mastocytosis identifies KIT D816V as a distinct and late event.

To explore the molecular profile and its prognostic implication in systemic mastocytosis (SM), we analyzed the mutation status of granulocyte-macrophage colony-forming progenitor cells (CFU-GM) in patients with KIT D816V(+) indolent SM (ISM, n=4), smoldering SM (SSM, n=2), aggressive SM (ASM, n=1), SM with associated clonal hematologic non-mast cell lineage disorder (SM-AHNMD, n=5) and ASM-AHNMD (n=7). All patients with (A)SM-AHNMD (n=12) carried 1-4 (median 3) additional mutations in 11 genes tested, most frequently TET2, SRSF2, ASXL1, CBL and EZH2. In multi-mutated (A)SM-AHNMD, KIT D816V(+) single-cell-derived CFU-GM colonies were identified in 8/12 patients (median 60%, range 0-95). Additional mutations were identified in CFU-GM colonies in all patients, and logical hierarchy analysis indicated that mutations in TET2, SRSF2 and ASXL1 preceded KIT D816V. In ISM/SSM, no additional mutations were detected and CFU-GM colonies were exclusively KIT D816V(-). These data indicate that (a) (A)SM-AHNMD is a multi-mutated neoplasm, (b) mutations in TET2, SRSF2 or ASXL1 precede KIT D816V in ASM-AHNMD,