Encoding Tyrosine Kinase Research Articles

Genetic evidence for efficacy of targeting IL-2, IL-6 and TYK2 signalling in the prevention of type 1 diabetes: a Mendelian randomisation study.

We aimed to investigate the genetic evidence that supports the repurposing of drugs already licensed or in clinical phases of development for prevention of type 1 diabetes. We obtained genome-wide association study summary statistics for the risk of type 1 diabetes, whole-blood gene expression and serum protein levels and investigated genetic polymorphisms near seven potential drug target genes. We used co-localisation to examine whether the same genetic variants that are associated with type 1 diabetes risk were also associated with the relevant drug target genetic proxies and used Mendelian randomisation to evaluate the direction and magnitude of the associations. Furthermore, we performed Mendelian randomisation analysis restricted to functional variants within the drug target genes. Co-localisation revealed that the blood expression levels of IL2RA (encoding IL-2 receptor subunit α [IL2RA]), IL6R (encoding IL-6 receptor [IL6R]) and IL6ST (encoding IL-6 cytokine family signal transducer [IL6ST]) shared the same causal variant with type 1 diabetes liability near the corresponding genes (posterior probabilities 100%, 96.5% and 97.0%, respectively). The OR (95% CI) of type 1 diabetes per 1-SD increase in the genetically proxied gene expression of IL2RA, IL6R and IL6ST were 0.22 (0.17, 0.27), 1.98 (1.48, 2.65) and 1.90 (1.45, 2.48), respectively. Using missense variants, genetically proxied TYK2 (encoding tyrosine kinase 2) expression levels were associated with type 1 diabetes risk (OR 0.61 [95% CI 0.54, 0.69]). Our findings support the targeting of IL-2, IL-6 and TYK2 signalling in prevention of type 1 diabetes. The analysis code is available at https://github.com/jkoskenniemi/T1DSCREEN , which also includes instructions on how to download the original GWAS summary statistics.

TAD border deletion at the Kit locus causes tissue-specific ectopic activation of a neighboring gene

Topologically associated domains (TADs) restrict promoter-enhancer interactions, thereby maintaining the spatiotemporal pattern of gene activity. However, rearrangements of the TADs boundaries do not always lead to significant changes in the activity pattern. Here, we investigated the consequences of the TAD boundaries deletion on the expression of developmentally important genes encoding tyrosine kinase receptors: Kit, Kdr, Pdgfra. We used genome editing in mice to delete the TADs boundaries at the Kit locus and characterized chromatin folding and gene expression in pure cultures of fibroblasts, mast cells, and melanocytes. We found that although Kit is highly active in both mast cells and melanocytes, deletion of the TAD boundary between the Kit and Kdr genes results in ectopic activation only in melanocytes. Thus, the epigenetic landscape, namely the mutual arrangement of enhancers and actively transcribing genes, is important for predicting the consequences of the TAD boundaries removal. We also found that mice without a TAD border between the Kit and Kdr genes have a phenotypic manifestation of the mutation — a lighter coloration. Thus, the data obtained shed light on the principles of interaction between the 3D chromatin organization and epigenetic marks in the regulation of gene activity.

A Discussion of Chronic Myeloid Leukemia

Chronic Myeloid Leukemia (CML) is a triphasic hematological malignancy characterized by the presence of the abnormal Philadelphia chromosome, linked to causing uncontrolled myeloid cell proliferation in the bone marrow and marked changes in the peripheral blood and bone marrow microenvironments. The discovery of the BCR-ABL1 fusion oncogene from the balanced translocation of chromosomes 9 and 22, creating the Philadelphia chromosome, and its encoded tyrosine kinase protein has been linked to causing uncontrolled cell proliferation, leading to a subsequent development of tyrosine kinase inhibitors (TKI). TKIs, along with traditional chemotherapy drugs and interferon treatment, have revolutionized CML treatment, enabling deep remissions and prolonging of the disease’s chronic phase. This review will introduce CML and comprehensively explore the epidemiology, molecular basis, pathology, diagnostic approaches, and therapeutic strategies for CML, including their mechanisms of action and challenges, such as TKI resistance, with a focus on TKIs as the workhorses of CML therapy. By reviewing the current known literature, this paper aims to contribute to and guide the pursuit of new knowledge and research.

An In silico Approach towards Finding the Cancer-Causing Mutations in Human MET Gene.

Mesenchymal-epithelial transition (MET) factor is a proto-oncogene encoding tyrosine kinase receptor with hepatocyte growth factor (HGF) or scatter factor (SF). It is found on the human chromosome number 7 and regulates the diverse cellular mechanisms of the human body. The impact of mutations occurring in the MET gene is demonstrated by their detrimental effects on normal cellular functions. These mutations can change the structure and function of MET leading to different diseases such as lung cancer, neck cancer, colorectal cancer, and many other complex syndromes. Hence, the current study focused on finding deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) and their subsequent impact on the protein's structure and functions, which may contribute to the emergence of cancers. These nsSNPs were first identified utilizing computational tools like SIFT, PROVEAN, PANTHER-PSEP, PolyPhen-2, I-Mutant 2.0, and MUpro. A total of 45359 SNPs of MET gene were accumulated from the database of dbSNP, and among them, 1306 SNPs were identified as non-synonymous or missense variants. Out of all 1306 nsSNPs, 18 were found to be the most deleterious. Moreover, these nsSNPs exhibited substantial effects on structure, binding affinity with ligand, phylogenetic conservation, secondary structure, and post-translational modification sites of MET, which were evaluated using MutPred2, RaptorX, ConSurf, PSIPRED, and MusiteDeep, respectively. Also, these deleterious nsSNPs were accompanied by changes in properties of MET like residue charge, size, and hydrophobicity. These findings along with the docking results are indicating the potency of the identified SNPs to alter the structure and function of the protein, which may lead to the development of cancers. Nonetheless, Genome-wide association study (GWAS) studies and experimental research are required to confirm the analysis of these nsSNPs.

Role of BRAF V600E Mutation in Papillary Thyroid Cancer

Talking about thyroid carcinomas leaves a fairly wide slope, in which it should be considered not only the variants and their clinical frequency, but the mutant genetic finding that gives preamble to the malignancy, its clinical variability, histological as well as the prognosis. It is important to note that the most frequent thyroid carcinoma in the population is papillary, with an index greater than 80% of all cases, being rare in pediatrics. The papillary thyroid subtype is the result of one of two possible alterations affecting the genes encoding tyrosine kinase, either in the RET gene of chromosome 10q11 or in the BRAF gene, by an early mutation in the MAP kinase signaling pathway. Statistically, it is known that the mutation in the BRAF gene represents most of the alterations that give rise to papillary thyroid carcinoma, and in turn, this BRAF gene presents an alteration in the amino acid 600, which gives rise to the BRAF 600E gene. That is why, in this research work focuses on the role BRAF V600E and papillary thyroid carcinoma, from the pathogenic mechanism that gives rise to the mutation, the genetic location of the mutation. Clinical and histopathological relationship with the BRAF mutation as well as prognosis and certain related complications are mentioned.

Abstract PL03-05: A framework for community-engaged participatory research in cancer genomic sequencing: A collaborative with sovereign tribal nations in the American southwest

Abstract While American Indian Tribes and communities are highly diverse in ethnicity, language, and culture, there is one unfortunate characteristic they share: profound cancer health disparities. Compounded by low rates of cancer screening and more limited access to healthcare, American Indians are more often diagnosed at later stages of disease and have the poorest outcomes in all types of cancer when compared to any other racial and ethnic group in the United States (Jamal et al. JNCI 2017; Sep; 109(9)). American Indians and Alaskan Natives (AI/AN) across the U.S. are impacted by a significantly higher incidence of several cancers when compared to non-Hispanic Whites (NHW): hepatocellular carcinoma; renal cell carcinoma; and cancers of the biliary tree (gall bladder and cholangiocarcinoma). In terms of mortality, AI/AN have the nation’s highest rate of death from liver cancer (2.2-fold > NHW) and a 1.9-fold higher rate of death from kidney cancer. The incidence of colorectal cancer in AI/AN communities has also increased significantly. The cause of these significant cancer disparities is undoubtedly multifactorial. In addition to low rates of cancer screening, other contributing factors include differences in access to healthcare and timely interventions; distinct cultural perspectives and beliefs regarding cancer etiology, screening, and treatment; differences in diet, obesity, metabolism, and risk behaviors (including tobacco, alcohol, and intravenous drug use); variable rates of vaccination and treatment for Hepatitis, HPV, and other viruses; ancestry-related biologic and genetic factors; and differences in environmental exposures. In the American Southwest, exposure of Tribal communities to environmental and carcinogenic toxins, including exposure to toxins such as aristolochic acid and aflatoxin, and to mining wastes from abandoned hard rock and uranium mines must also be considered. Experimental and epidemiologic studies have linked exposure to mining wastes that contaminate western watersheds (containing highly toxic metal mixtures of arsenic, uranium, cadmium, and other metals) to increased cancer risk in Tribal and non-Tribal communities (Environ Health Perspect. 2014;122(4):363; Cancer Epidemiol Biomark Prev. 2013;22(11):1944.).A virtually unexplored factor which may also contribute to cancer health disparities in AI/AN communities is whether the cancers that arise in American Indians have a distinct spectrum of somatic and germline genomic mutations (somatic and germline) resulting from these factors. Unfortunately, AI/AN cancer patients have been strikingly understudied to date, accounting for < 0.5% of all patients studied in national cancer genomic initiatives. Cancer genomic studies previously conducted by our team of investigators in the NCI TARGET Project (https://ocg.cancer.gov > programs > target) focused on high-risk acute lymphoblastic leukemia (ALL) discovered that patients with a high degree of indigenous genetic ancestry had a unique spectrum of mutations in genes encoding tyrosine kinases or genes regulating tyrosine kinase pathways. All patients with this mutation spectrum had a significantly poorer overall outcome, despite treatment with intensive therapies. Recent studies have found a unique spectrum and frequency of mutations and mutational signatures in kidney cancers arising in indigenous communities (Trent, J. et al; unpublished). Our NCI-funded Participant Engagement-Cancer Genome Sequencing (PE-CGS) Research Center (NCI U2C CA252973: Engagement of American Indians of Southwestern Tribal Nations in Cancer Genomic Sequencing; MPIs: Willman and Jeffrey Trent, PhD) is seeking to overcome this knowledge gap through direct participant engagement and collaborative research partnerships with Tribal nations and communities. A proper framework for engagement of indigenous Tribal Nations and tribal participants in research includes respect for Tribal sovereignty; engagement of participants and communities in project selection and oversight; assuring that the research is beneficent; the use of culturally-appropriate approaches for informed consent; appropriate data sharing, assurance of data privacy, and data interpretation and communication, including the need to engage AI/AN participants and communities in the development of culturally appropriate interpretive data narratives; sensitivities regarding collection and approval for use of biospecimens, particularly future use; concerns over genetic privacy, protection of individual identity, and assurance that molecular means of ancestry determination in individual Tribal members will not interfere with Tribal means of cultural identify and their Tribal membership; and joint sharing in intellectual property and the benefits of discoveries. It is our hypothesis that through appropriate participant and community engagement and comprehensive genomic sequencing, we will discover novel somatic and germline mutations, differences in the spectrum and/or frequency of cancer-promoting mutations, and genome-wide mutational signatures reflective of behaviors and exposures, that can ultimately be translated to improved cancer screening, precision prevention, and therapeutic intervention in American Indian participants and communities. Citation Format: Cheryl L. Willman. A framework for community-engaged participatory research in cancer genomic sequencing: A collaborative with sovereign tribal nations in the American southwest [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr PL03-05.

Genetic mechanisms of critical illness in COVID-19.

Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P=1.65×10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P=2.3×10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P=3.98×10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P=4.99×10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice.

Diagnostyka i leczenie mastocytozy układowej — stanowisko ekspertów

Systemic mastocytosis (SM) is a rare hematological malignancy characterized by an abnormal expansion and accumulation of pathological mast cells in bone marrow and other organs including skin, liver, spleen and lymph nodes. The clinical manifestation can be extremely heterogeneous, from limited skin changes to multi-organ involvement or mast cell tumors. The median survival of patients diagnosed with indolent form is comparable to healthy population, while prognosis for patients with advanced disease is poor, with an estimated survival ranging from several months to several years. In most patients (> 90%), a somatic mutation in codon 816 of the c-KIT gene encoding tyrosine kinase receptor is detected. Additional molecular abnormalities and even coexistence of other hematological cancers, e.g . acute leukemia, are also observed. Regardless of the form of disease or serum tryptase concentration, patients are exposed to symptoms resulting from the release of mast cell mediators — most often itching, paroxysmal redness and blisters, and general mediator-induced symptoms — such as nausea, vomiting, diarrhea, abdominal pain, hypotensive episodes, fatigue, headache, fever, shortness of breath, osteopenia, osteoporosis and severe anaphylactic reactions. This paper presents current outlook on the diagnostic and treatment process of SM, taking into account the interdisciplinary aspects of the disease.

Chromatin accessibility mapping of the striatum identifies tyrosine kinase FYN as a therapeutic target for heroin use disorder

The current opioid epidemic necessitates a better understanding of human addiction neurobiology to develop efficacious treatment approaches. Here, we perform genome-wide assessment of chromatin accessibility of the human striatum in heroin users and matched controls. Our study reveals distinct neuronal and non-neuronal epigenetic signatures, and identifies a locus in the proximity of the gene encoding tyrosine kinase FYN as the most affected region in neurons. FYN expression, kinase activity and the phosphorylation of its target Tau are increased by heroin use in the post-mortem human striatum, as well as in rats trained to self-administer heroin and primary striatal neurons treated with chronic morphine in vitro. Pharmacological or genetic manipulation of FYN activity significantly attenuates heroin self-administration and responding for drug-paired cues in rodents. Our findings suggest that striatal FYN is an important driver of heroin-related neurodegenerative-like pathology and drug-taking behavior, making FYN a promising therapeutic target for heroin use disorder.

Expression of Active Staphylococcus aureus Tyrosine Kinases in a Human Cell Line.

Many bacteria encode tyrosine kinases that are structurally unrelated to their eukaryotic counterparts and are termed BY-kinases. Two BY-kinases, CapB1 and CapB2, have been identified in the Staphylococcus aureus genome. Although CapB1 and CapB2 share more than 70% homology, earlier studies with purified enzymes did not find any evident kinase activity in CapB1, whereas CapB2 was autophosphorylated on a C-terminal tyrosine cluster in the presence of the kinase modulator proteins CapA1 or CapA2. For the convenient analysis of BY-kinases, we attempted to express CapB2 in an active form in a mammalian cell line. To this end, the C-terminal activation domain of CapA1 was attached to the N-terminus of CapB2, and the resulting CapA1/CT-CapB2 chimera was further fused with various tags and transfected into HEK293T cells. Immunoblotting analyses showed that when fluorescent protein tags were attached to the N-terminus, CapA1/CT-CapB2 was both expressed and tyrosine phosphorylated in HEK293T cells. Mutation of the ATP-binding lysine abrogated tyrosine phosphorylation, indicating that tyrosine phosphorylation was catalyzed by the transfected bacterial kinase and not by endogenous cellular enzymes. Unexpectedly, mutation of the C-terminal tyrosine cluster did not abolish autophosphorylation. Further analyses revealed that CapA1/CT-CapB2 phosphorylated not only itself but also the attached fluorescent protein tag. Several domains and residues important for tyrosine kinase activity were identified from the production of various mutants. We also present data that CapB1, which was previously thought to be catalytically inert, may possess intrinsic kinase activity.

Mapping of the tyrosine kinase receptors trkA (NTRK1), trkB (NTRK2) and trkC(NTRK3) to human chromosomes 1q22, 9q22 and 15q25 by fluorescence in situ hybridization.

trk (NTRK) genes encode tyrosine kinase transmembrane receptors that are stimulated by neurotrophins, and are responsible for the transduction of signals controlling neuropoiesis and neuron survival in the central and peripheral nervous system, trkA gene has earlier been assigned to three different loci on chromosome 1. To resolve these conflicting results, and confirm the localization of trkB and trkC, probes specific to each of these related genes were constructed and used in fluorescent in situ hybridization on human metaphase cells. Our results indicate that trkA, trkB and trkC are located in chromosome bands 1q22, 9q22 and 15q25, respectively.

Targeting Oncogenic Signaling in Mutant FLT3 Acute Myeloid Leukemia: The Path to Least Resistance.

The identification of recurrent driver mutations in genes encoding tyrosine kinases has resulted in the development of molecularly-targeted treatment strategies designed to improve outcomes for patients diagnosed with acute myeloid leukemia (AML). The receptor tyrosine kinase FLT3 is the most commonly mutated gene in AML, with internal tandem duplications within the juxtamembrane domain (FLT3-ITD) or missense mutations in the tyrosine kinase domain (FLT3-TKD) present in 30–35% of AML patients at diagnosis. An established driver mutation and marker of poor prognosis, the FLT3 tyrosine kinase has emerged as an attractive therapeutic target, and thus, encouraged the development of FLT3 tyrosine kinase inhibitors (TKIs). However, the therapeutic benefit of FLT3 inhibition, particularly as a monotherapy, frequently results in the development of treatment resistance and disease relapse. Commonly, FLT3 inhibitor resistance occurs by the emergence of secondary lesions in the FLT3 gene, particularly in the second tyrosine kinase domain (TKD) at residue Asp835 (D835) to form a ‘dual mutation’ (ITD-D835). Individual FLT3-ITD and FLT3-TKD mutations influence independent signaling cascades; however, little is known about which divergent signaling pathways are controlled by each of the FLT3 specific mutations, particularly in the context of patients harboring dual ITD-D835 mutations. This review provides a comprehensive analysis of the known discrete and cooperative signaling pathways deregulated by each of the FLT3 specific mutations, as well as the therapeutic approaches that hold the most promise of more durable and personalized therapeutic approaches to improve treatments of FLT3 mutant AML.

Abstract LB-232: Derazantinib (ARQ 087) pharmacodynamics: Alterations in FGF19/21/23 and phosphate in patients with cholangiocarcinoma

Abstract Background: Fibroblast growth factors (FGFs) and their receptors (FGFRs) play important roles in cell proliferation, cell differentiation, cell migration, cell survival, protein synthesis, and angiogenesis. The FGFR family consist of four genes encoding tyrosine kinase receptors (FGFR1, FGFR2, FGFR3, and FGFR4). Dysregulation of FGFR signaling has been implicated in a number of developmental syndromes as well as cancers, e.g., intrahepatic cholangiocarcinoma (iCCA), squamous non-small cell lung cancer, small cell lung cancer, gastric, liver, breast, ovarian, endometrial, and bladder carcinomas, fueling significant interest in FGFRs as targets for therapeutic intervention. In human cancers, FGFRs have been found to be dysregulated by multiple mechanisms, including aberrant expression, mutations, chromosomal rearrangements, and amplifications. Members of the FGF19 ligand subfamily, FGFs 19, 21 and 23, are involved in the regulation of bile acid synthesis, glucose and lipid metabolism, and phosphate homeostasis, respectively. Unlike other FGFR ligands that act locally, the FGF19 subfamily circulate throughout the body, and can act as endocrine hormones at organs distant from their site of synthesis. The wide circulation of FGFs 19, 21, 23 makes them excellent potential biomarkers for FGFR inhibition. Study Design: 29 patients (18 women, 11 men, median age 58.7 years, all white) with FGFR2 gene positive fusion iCCA were enrolled and treated with derazantinib (dose range 300-400mg QD) at eight sites in the United States and Italy between August 2014 and October 2017 as part of clinical trial ARQ 087-101 [NCT01752920]. Patients' plasma samples were collected (on Day 1, 8, 15, 22 of Cycle 1 and Day 1 of Cycles 2-6) and analyzed for levels of FGF & phosphate. FGF levels were quantified using commercially available ELISA kits for FGF-19 and 21 (R&D Systems, Minneapolis, MN), and FGF-23 (EMD-Millipore, Billerica, MA). Results: Preliminary data analysis showed clear increase in mean FGF19, 23, and phosphate levels in iCCa patients treated with derazantinib. On Cycle 2 Day 1, phosphate levels on average increased by 40% over baseline. FGF19 and FGF23 increased by 300% and 140%, respectively. Final results and any additional findings will be presented at the meeting. Conclusions: The changes in FGF19, FGF23, and phosphate observed during treatment suggest that at the recommended phase II dose of derazantinib (300 mg QD), clinical signs of target engagement are detectable. Additional data to demonstrate potential correlation between FGFs/phosphate levels and clinical outcomes, including response and toxicity will be presented. DeLIVERr, a pivotal study of derazantinib in patients with FGFR2 gene fusion positive iCCA is ongoing (NCT03230318). Citation Format: Terence Hall, Vincenzo Mazzaferro, Bassel El-Rayes, Christian Cotsoglou, William P. Harris, Nevana Damjanov, Gianluca Masi, Lorenza Rimassa, Nicola Personeni, Vittorina Zagonel, Kyriakos P. Papadopoulos, Sherrie Bhoori, Michele Droz-Dit-Busset, Walid Shaib, Maria Lamar, Julia Kazakin, Brian Schwartz, Yunxia Wang, Ronald E. Savage. Derazantinib (ARQ 087) pharmacodynamics: Alterations in FGF19/21/23 and phosphate in patients with cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-232.

PDGFRA mRNA overexpression is associated with regional metastasis and reduced survival in oral squamous cell carcinoma

Platelet-derived growth factor alpha (PDGFRA) is a gene encoding tyrosine kinase receptor and both EGFR and PDGFRA activate tyrosine kinases. The implication of PGFRA in many cancers and its prognostic significance irrespective to EGFR status in spinal chordoma, gliomas, and uterine cancers have shown a need for its investigation in oral squamous cell carcinoma (OSCC). We investigated the prognostic value of PDGFRA mRNA expression in OSCC. The study was conducted in the department of oral maxillofacial surgery-head and neck oncology, at a tertiary hospital. The data on PDGFRA mRNA expression and immunohistochemical staining status in primary OSCC patients treated for curative surgery from 2010 to 2012 were analyzed. Univariate and multivariate analyses were performed with other cofactors for survival. A total of 114 consecutive patients with primary OSCC who received treatment were studied. Thirty-one patients died of the disease. Strong PDGFRA immunohistochemical staining and high expression of PDGFRA mRNA were associated with positive pN status (P<.001), disease-free survival (P<.001), and overall survival (P<.001) in multivariate cox regression when all other factors such as pN status and histological grading were analyzed. Kaplan-Meier analysis revealed that the 2-year survival and 3-year survival of patients with PDGFRA mRNA low expression were 96.83%. However, 2-year survival for PDGFRA mRNA high expression level was 59.64%, which decreased to 45.57% by 3-years. PDGFRA overexpression in oral SCC, in respect to strong PDGFRA immunohistochemical staining and high PDGFRA mRNA expression, was positively associated with regional metastasis and reduced patient survival.

Expression of the c-MET, HGF and VEGF biomarkers in intestinal and diffuse gastric cancer in the Brazilian population: a pilot study for the standardization of the quantitative PCR technique

BackgroundGastric carcinoma (GC) is the third leading cause of death among malignant tumors worldwide, causing approximately 900,000 deaths/year. Changes in oncogenes that encode tyrosine kinase receptors play an important role in the pathogenesis of GC. MET gene is a proto-oncogene that encodes a tyrosine kinase receptor c-MET and it is required for embryonic development and tissue repair. The hepatocyte growth factor (HGF) is the only known ligand for c-Met receptor. The MET oncogene activation suppresses apoptosis and promotes the survival, proliferation, migration, differentiation and angiogenesis of cells. Among the angiogenic factors, VEGF is the main regulator. Its biological function includes the promotion of endothelial cells mitosis to stimulate cells proliferation. These biomarkers expression in GC is relatively recent and population-based studies are required to define the expression pattern. The aim of this study was to determine qPCR technical standardization to evaluate quantitatively, in paraffin tissue samples, the presence of gene 23 expression of the MET, HGF and VEGF in diffuse and intestinal GC types.MethodsTwenty GC patients were studied, 10 patients were intestinal-type GC (average age 72.1 years) and 10 diffuse-type (average age 50.1 years). In all patients, tissue samples were analyzed from the tumor and distant areas of the tumor tissue. The relative expressions of the tumor markers c-Met, HGF and VEGF were performed by qPCR technique by comparing tumor and non-tumoral samples and they were normalized with the GAPDH constitutive gene. Statistical analysis was performed through T-test.ResultsFor c-Met, 18/20 (90%) patients expressed the marker and 9/20 (45%) overexpressed this gene, in which three were intestinal-type GC and six were diffuse-type GC. For HGF, only 7/20 (35%) patients expressed this gene and it was overexpressed in 4/20 (20%), in which two were intestinal-type GC and two were diffuse-type GC. For VEGF, 20/20 (100%) patients expressed this marker and in 12/20 (60%) were observed overexpression, in which eight patients had diffuse-type GC and four had intestinal-type GC.ConclusionsqPCR technique was standardized and suitable for expression analysis of the three biomarkers using paraffin embedded tissue samples. Further studies should be carried out to characterize the expression pattern of these biomarkers in GC in the Brazilian population.

Abstract SY14-04: Cancer health disparities in American Indian and Alaskan Native populations

Abstract SY14-04: Cancer health disparities in American Indian and Alaskan Native populations

Evaluation of the relationship between c-Kit expression and mean platelet volume in classic Kaposi's sarcoma.

Backgroundc-Kit is a proto-oncogene that encodes tyrosine kinase receptor (CD117). Mean platelet volume (MPV) is a useful marker, providing information on platelet function and diameter.ObjectiveTo investigate c-Kit expression and intensity in patients with Kaposi's sarcoma (KS) and to investigate the relation between Ki-67 proliferation and MPV.MethodsA total of 32 patients, diagnosed with classic cutaneous KS, were included in this study. We reevaluated the histopathological reports with the preparations, confirmed the diagnosis and then determined the patients' histopathological stages. c-Kit expression and Ki-67 proliferation were investigated immunohistochemically in KS cases, while MPV in all cases was checked.ResultsAlthough c-Kit expression was detected in 22 cases (68.8%), it was not expressed in 10 cases (31.2%). We detected 8 cases with + (25%), 6 with ++ (18.8%) and 8 with +++ (25%). Ki-67 expression was 5.0% (min-max 1.0-20.0). Relapse was observed in 5 cases (15.6%) out of 32. There was positive correlation between c-Kit expression and MPV (rs=0.598, p<0.001), and between c-Kit intensity and MPV (rs=0.588, p<0.001).Conclusionc-Kit is highly positive in KS. c-Kit positivity indicates a high risk of tumor growth, invasion and relapse. Furthermore, c-Kit expression stimulates megakaryocytes to release young and large thrombocytes into the periphery. Thus, high MPV, c-Kit expression and immunostaining intensity indicate high invasion and relapse in KS subjects.

Parallel targeted next generation sequencing of childhood and adult acute myeloid leukemia patients reveals uniform genomic profile of the disease.

The age-specific differences in the genetic mechanisms of myeloid leukemogenesis have been observed and studied previously. However, NGS technology has provided a possibility to obtain a large amount of mutation data. We analyzed DNA samples from 20 childhood (cAML) and 20 adult AML (aAML) patients, using NGS targeted sequencing. The average coverage of high-quality sequences was 2981×per amplicon. A total of 412 (207 cAML, 205 aAML) variants in the coding regions were detected; out of which, only 122 (62 cAML and 60 aAML) were potentially protein-changing. Our results confirmed that AML contains small number of genetic alterations (median 3 mutations/patient in both groups). The prevalence of the most frequent single gene AML associated mutations differed in cAML and aAML patient cohorts: IDH1 (0% cAML, 5% aAML), IDH2 (0% cAML, 10% aAML), NPM1 (10% cAML, 35% aAML). Additionally, potentially protein-changing variants were found in tyrosine kinase genes or genes encoding tyrosine kinase associated proteins (JAK3, ABL1, GNAQ, and EGFR) in cAML, while among aAML, the prevalence is directed towards variants in the methylation and histone modifying genes (IDH1, IDH2, and SMARCB1). Besides uniform genomic profile of AML, specific genetic characteristic was exclusively detected in cAML and aAML.

The Role of CagA in the Gastric Biology of Helicobacter pylori.

See related article by Blaser et al., [Cancer Res 1995;55:2111–5][1] . Visit the Cancer Research 75th Anniversary [timeline][2]. Helicobacter pylori (H. pylori) was discovered in 1983 by the Australian scientists Warren and Marshall as a gastric pathogen, causing peptic ulcer disease. In 2005,

The Streptococcus pyogenes orphan protein tyrosine phosphatase, SP-PTP, possesses dual specificity and essential virulence regulatory functions.

Group A Streptococcus (GAS) is a human pathogen that causes high morbidity and mortality. GAS lacks a gene encoding tyrosine kinase but contains one encoding tyrosine phosphatase (SP-PTP). Thus, GAS is thought to lack tyrosine phosphorylation, and the physiological significance of SP-PTP is, therefore, questionable. Here, we demonstrate that SP-PTP possesses dual phosphatase specificity for Tyr- and Ser/Thr-phosphorylated GAS proteins, such as Ser/Thr kinase (SP-STK) and the SP-STK-phosphorylated CovR and WalR proteins. Phenotypic analysis of GAS mutants lacking SP-PTP revealed that the phosphatase activity per se positively regulates growth, cell division and the ability to adhere to and invade host cells. Furthermore, A549 human lung cells infected with GAS mutants lacking SP-PTP displayed increased Ser-/Thr-/Tyr-phosphorylation. SP-PTP also differentially regulates the expression of ∼50% of the total GAS genes, including several virulence genes potentially through the two-component regulators, CovR, WalR and PTS/HPr regulation of Mga. Although these mutants exhibit attenuated virulence, a GAS mutant overexpressing SP-PTP is hypervirulent. Our study provides the first definitive evidence for the presence and importance of Tyr-phosphorylation in GAS and the relevance of SP-PTP as an important therapeutic target.