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1.
J Natl Compr Canc Netw ; 22(2 D)2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38862008

RESUMO

Colorectal cancer (CRC) is the fourth most frequently diagnosed cancer and the second leading cause of cancer death in the United States. Management of disseminated metastatic CRC involves various active drugs, either in combination or as single agents. The choice of therapy is based on consideration of the goals of therapy, the type and timing of prior therapy, the mutational profile of the tumor, and the differing toxicity profiles of the constituent drugs. This manuscript summarizes the data supporting the systemic therapy options recommended for metastatic CRC in the NCCN Guidelines for Colon Cancer.


Assuntos
Neoplasias do Colo , Humanos , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/terapia , Neoplasias do Colo/patologia , Neoplasias do Colo/tratamento farmacológico , Oncologia/normas , Oncologia/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Estados Unidos
3.
J Natl Compr Canc Netw ; 21(6): 653-677, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37308125

RESUMO

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.


Assuntos
Neoplasias do Ânus , Carcinoma de Células Escamosas , Humanos , Biópsia , Oncologia
4.
World J Hepatol ; 15(2): 225-236, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36926233

RESUMO

BACKGROUND: Cirrhosis and its complications develop in a subgroup of patients with non-alcoholic fatty liver disease (NASH). Early detection of liver fibrosis represents an important goal of clinical care. AIM: To test the hypothesis that the development of cirrhosis in nonalcoholic fatty liver disease patients is preceded by the long-term trends of platelet counts and Fib-4 scores. METHODS: We identified all patients in our healthcare system who had undergone fibrosis staging by liver biopsy or magnetic resonance elastography (MRE) for non-alcoholic fatty liver disease during the past decade (n = 310). Platelet counts, serum glutamic-pyruvic transaminase and serum glutamic oxalacetic transaminase values preceding the staging tests were extracted from the electronic medical record system, and Fib-4 scores were calculated. Potential predictors of advanced fibrosis were evaluated using multivariate regression analysis. RESULTS: Significant decreases in platelet counts and increases in Fib-4 scores were observed in all fibrosis stages, particularly in patients with cirrhosis. In the liver biopsy group, the presence of cirrhosis was best predicted by the combination of the Fib-4 score at the time closest to staging (P < 0.0001), the presence of diabetes (P = 0.0001), and the correlation coefficient of the preceding time-dependent drop in platelet count (P = 0.044). In the MRE group, Fib4 score (P = 0.0025) and platelet drop (P = 0.0373) were significant predictors. In comparison, the time-dependent rise of the Fib-4 score did not contribute in a statistically significant way. CONCLUSION: Time-dependent changes in platelet counts and Fib-4 scores contribute to the prediction of cirrhosis in NASH patients with biopsy- or MRE-staged fibrosis. Their incorporation into predictive algorithms may assist in the earlier identification of high-risk patients.

6.
Ups J Med Sci ; 1272022.
Artigo em Inglês | MEDLINE | ID: mdl-35173908

RESUMO

BACKGROUND: Electronic medical records (EMRs) are adopted for storing patient-related healthcare information. Using data mining techniques, it is possible to make use of and derive benefit from this massive amount of data effectively. We aimed to evaluate validity of data extracted by the Customized eXtraction Program (CXP). METHODS: The CXP extracts and structures data in rapid standardised processes. The CXP was programmed to extract TNFα-native active ulcerative colitis (UC) patients from EMRs using defined International Classification of Disease-10 (ICD-10) codes. Extracted data were read in parallel with manual assessment of the EMR to compare with CXP-extracted data. RESULTS: From the complete EMR set, 2,802 patients with code K51 (UC) were extracted. Then, CXP extracted 332 patients according to inclusion and exclusion criteria. Of these, 97.5% were correctly identified, resulting in a final set of 320 cases eligible for the study. When comparing CXP-extracted data against manually assessed EMRs, the recovery rate was 95.6-101.1% over the years with 96.1% weighted average sensitivity. CONCLUSION: Utilisation of the CXP software can be considered as an effective way to extract relevant EMR data without significant errors. Hence, by extracting from EMRs, CXP accurately identifies patients and has the capacity to facilitate research studies and clinical trials by finding patients with the requested code as well as funnel down itemised individuals according to specified inclusion and exclusion criteria. Beyond this, medical procedures and laboratory data can rapidly be retrieved from the EMRs to create tailored databases of extracted material for immediate use in clinical trials.


Assuntos
Mineração de Dados , Registros Eletrônicos de Saúde , Mineração de Dados/métodos , Bases de Dados Factuais , Humanos , Classificação Internacional de Doenças
7.
J Pancreat Cancer ; 6(1): 96-101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-34095737

RESUMO

Background: Liver parenchyma that resides outside of the normal hepatic confines is defined as accessory liver if in communication with the native biliary tree, or ectopic liver (EL) if it is not. EL can develop in a variety of tissues, including but not limited to the gallbladder, the hepatic ligaments, the pancreas, and retroperitoneum. EL has an increased propensity for malignant degeneration resulting in hepatocellular carcinoma (HCC). Presentation: A 67-year-old Korean male presented with epigastric discomfort and was found to have an elevation in his transaminases. Cross-sectional imaging demonstrated a 1.3 cm solid mass in the body of the pancreas with features concerning for either a pancreatic ductal adenocarcinoma or pancreatic neuroendocrine tumor. Subsequent endoscopic ultrasound and fine needle aspiration demonstrated cells of epithelial origin with hepatocellular differentiation. A robotic-assisted distal pancreatectomy and splenectomy was performed with final pathology demonstrating a well-differentiated HCC. Conclusions: EL with malignant degeneration resulting in HCC requires surgical excision. The majority of patients reported with EL resulting in HCC in the pancreas have had the tumors located in the body and tail. Therefore, definitive treatment requires distal pancreatectomy and splenectomy. Herein, we describe the presentation, workup, and definitive treatment of HCC arising in the pancreas.

8.
ACG Case Rep J ; 6(2): e00003, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31616712

RESUMO

Idiosyncratic hepatotoxicity is a leading reason for the discontinuation or dose modification of Food and Drug Administration (FDA)-approved medications in the United States. We report the case of a 53-year-old woman with chronic myeloid leukemia who developed acute cholestatic hepatitis in response to the tyrosine kinase inhibitor nilotinib. Nilotinib was discontinued, and the patient's liver function tests normalized over the next 3 months. We conclude that nilotinib may cause life-threatening hepatotoxicity and recommend that patients on the medication undergo regular monitoring of their liver tests.

9.
Am J Clin Oncol ; 42(10): 761-766, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31569128

RESUMO

BACKGROUND: Primary systemic therapy in resectable pancreatic cancer is currently under investigation. FOLFIRINOX has been shown to be effective in both the adjuvant and metastatic settings and is increasingly being used on and off study in the neoadjuvant setting. The objective pathologic response elicited by this regimen in truly resectable disease has not as yet been widely reported. METHODS: This analysis focuses on 14 patients with resectable pancreatic cancer who were treated in a pilot study of primary systemic therapy, using 4 cycles of neoadjuvant FOLFIRINOX before surgery. A dedicated pancreatic pathologist reviewed all of the subsequent surgical specimens to assess the degree of tumor regression elicited by this approach, according to the scoring system proposed by Evans. RESULTS: Four patients (28.6%) had Evans grade I, 4 (28.6%) Evans grade IIa, 2 (14.2%) Evans grade IIb, and 4 (28.6%) Evans grade III response to the primary systemic therapy. There were no Evans grade IV responses. CONCLUSIONS: The results are intriguing with 28% of the specimens showing destruction of <10% of tumor cells, and only 28% achieving >90% destruction of tumor cells. The significant variation in response once again confirms the known heterogeneity in the biology of this cancer and clearly FOLFIRINOX is not equally effective in all patients. Future studies evaluating primary systemic therapy in pancreatic cancer should examine the optimal duration of therapy before surgery and should include a standardized pathologic grading scheme to better enable comparison of results.


Assuntos
Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Neoadjuvante/métodos , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Adenocarcinoma/terapia , Adulto , Idoso , Biópsia por Agulha , Causas de Morte , Quimioterapia Adjuvante , Estudos de Coortes , Terapia Combinada , Intervalo Livre de Doença , Feminino , Fluoruracila/uso terapêutico , Hospitais Universitários , Humanos , Imuno-Histoquímica , Irinotecano/uso terapêutico , Estimativa de Kaplan-Meier , Leucovorina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Oxaliplatina/uso terapêutico , Pancreatectomia/métodos , Neoplasias Pancreáticas/terapia , Projetos Piloto , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
10.
J Clin Invest ; 129(2): 902-914, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30667372

RESUMO

Graft-versus-host disease (GVHD) is a complication of hematopoietic stem cell transplantation (HSCT) that affects multiple organs. GVHD-associated intestinal damage can be separated into two distinct phases, initiation and propagation, which correspond to conditioning-induced damage and effector T cell activation and infiltration, respectively. Substantial evidence indicates that intestinal damage induced by pretransplant conditioning is a key driver of GVHD initiation. Here, we aimed to determine the impact of dysregulated intestinal permeability on the subsequent GVHD propagation phase. The initiation phase of GVHD was unchanged in mice lacking long MLCK (MLCK210), an established regulator of epithelial tight junction permeability. However, MLCK210-deficient mice were protected from sustained barrier loss and exhibited limited GVHD propagation, as indicated by reduced histopathology, fewer CD8+ effector T cells in the gut, and improved overall survival. Consistent with these findings, intestinal epithelial MLCK210 expression and enzymatic activity were similarly increased in human and mouse GVHD biopsies. Intestinal epithelial barrier loss mediated by MLCK210 is therefore a key driver of the GVHD propagation. These data suggest that inhibition of MLCK210-dependent barrier regulation may be an effective approach to limiting GVHD progression.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Doença Enxerto-Hospedeiro/imunologia , Transplante de Células-Tronco Hematopoéticas , Mucosa Intestinal/imunologia , Quinase de Cadeia Leve de Miosina/imunologia , Junções Íntimas/imunologia , Aloenxertos , Animais , Linfócitos T CD8-Positivos/patologia , Feminino , Doença Enxerto-Hospedeiro/patologia , Mucosa Intestinal/patologia , Camundongos , Camundongos Endogâmicos BALB C , Junções Íntimas/patologia
11.
Nat Commun ; 9(1): 4827, 2018 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-30425251

RESUMO

In the originally published version of this Article, the affiliation details for Kevin P. White inadvertently omitted 'Tempus Labs, Chicago, IL, 60654, USA'. This has now been corrected in both the PDF and HTML versions of the Article.

12.
Nat Commun ; 9(1): 1793, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29728604

RESUMO

The oligometastasis hypothesis suggests a spectrum of metastatic virulence where some metastases are limited in extent and curable with focal therapies. A subset of patients with metastatic colorectal cancer achieves prolonged survival after resection of liver metastases consistent with oligometastasis. Here we define three robust subtypes of de novo colorectal liver metastasis through integrative molecular analysis. Patients with metastases exhibiting MSI-independent immune activation experience the most favorable survival. Subtypes with adverse outcomes demonstrate VEGFA amplification in concert with (i) stromal, mesenchymal, and angiogenic signatures, or (ii) exclusive NOTCH1 and PIK3C2B mutations with E2F/MYC activation. Molecular subtypes complement clinical risk stratification to distinguish low-risk, intermediate-risk, and high-risk patients with 10-year overall survivals of 94%, 45%, and 19%, respectively. Our findings provide a framework for integrated classification and treatment of metastasis and support the biological basis of curable oligometastatic colorectal cancer. These concepts may be applicable to many patients with metastatic cancer.


Assuntos
Neoplasias Colorretais/genética , Amplificação de Genes , Neoplasias Hepáticas/genética , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Classe II de Fosfatidilinositol 3-Quinases/genética , Neoplasias Colorretais/patologia , Neoplasias Colorretais/terapia , Feminino , Perfilação da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/terapia , Masculino , Pessoa de Meia-Idade , Receptor Notch1/genética , Fator A de Crescimento do Endotélio Vascular/genética
13.
ACG Case Rep J ; 4: e21, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28184378

RESUMO

Relapse of hepatitis C virus (HCV) genotype 1 infection after combination therapy with sofosbuvir and ledipasvir is unusual. We report a treatment-naïve, non-cirrhotic patient in whom the relapse of genotype 1b HCV infection was accompanied by de novo cryoglobulinemic vasculitis and glomerulonephritis, requiring hemodialysis for acute renal failure. Sequence analysis revealed several resistance-associated variants in the HCV NS5a gene but not in NS3/4A. The patient's vasculitis was successfully treated with immunosuppression and plasmapheresis, followed by retreatment of HCV with a combination of sofosbuvir, simeprevir, and ribavirin. The patient achieved sustained virological response, recovered his renal function, and remains in remission from cryoglobulinemia.

14.
J Cell Sci ; 130(1): 243-259, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27802160

RESUMO

Epithelia within tubular organs form and expand lumens. Failure of these processes can result in serious developmental anomalies. Although tight junction assembly is crucial to epithelial polarization, the contribution of specific tight junction proteins to lumenogenesis is undefined. Here, we show that ZO-1 (also known as TJP1) is necessary for the formation of single lumens. Epithelia lacking this tight junction scaffolding protein form cysts with multiple lumens and are defective in the earliest phases of polarization, both in two and three dimensions. Expression of ZO-1 domain-deletion mutants demonstrated that the actin-binding region and U5-GuK domain are crucial to single lumen development. For actin-binding region, but not U5-GuK domain, mutants, this could be overcome by strong polarization cues from the extracellular matrix. Analysis of the U5-GuK binding partners shroom2, α-catenin and occludin showed that only occludin deletion led to multi-lumen cysts. Like ZO-1-deficiency, occludin deletion led to mitotic spindle orientation defects. Single lumen formation required the occludin OCEL domain, which binds to ZO-1. We conclude that ZO-1-occludin interactions regulate multiple phases of epithelial polarization by providing cell-intrinsic signals that are required for single lumen formation.


Assuntos
Actinas/metabolismo , Técnicas de Cultura de Células/métodos , Polaridade Celular , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Ocludina/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo , Linhagem Celular , Proliferação de Células , Técnicas de Silenciamento de Genes , Humanos , Mitose , Morfogênese , Fenótipo , Ligação Proteica , Transporte Proteico , Junções Íntimas/metabolismo , Proteína da Zônula de Oclusão-1/química , alfa Catenina/metabolismo
15.
Am J Physiol Gastrointest Liver Physiol ; 311(3): G396-411, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27229120

RESUMO

The Hippo pathway effector Yes-associated protein (YAP) regulates liver size by promoting cell proliferation and inhibiting apoptosis. However, recent in vivo studies suggest that YAP has important cellular functions other than controlling proliferation and apoptosis. Transgenic YAP expression in mouse hepatocytes results in severe jaundice. A possible explanation for the jaundice could be defects in adherens junctions that prevent bile from leaking into the blood stream. Indeed, immunostaining of E-cadherin and electron microscopic examination of bile canaliculi of Yap transgenic livers revealed abnormal adherens junction structures. Using primary hepatocytes from Yap transgenic livers and Yap knockout livers, we found that YAP antagonizes E-cadherin-mediated cell-cell junction assembly by regulating the cellular actin architecture, including its mechanical properties (elasticity and cortical tension). Mechanistically, we found that YAP promoted contractile actin structure formation by upregulating nonmuscle myosin light chain expression and cellular ATP generation. Thus, by modulating actomyosin organization, YAP may influence many actomyosin-dependent cellular characteristics, including adhesion, membrane protrusion, spreading, morphology, and cortical tension and elasticity, which in turn determine cell differentiation and tissue morphogenesis.


Assuntos
Citoesqueleto de Actina/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Junções Aderentes/fisiologia , Hepatócitos/fisiologia , Fosfoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Caderinas , Proteínas de Ciclo Celular , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fosfoproteínas/genética , Fatores de Transcrição de Domínio TEA , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAP
16.
Sci Transl Med ; 6(243): 243ra87, 2014 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-24990882

RESUMO

Previous studies have shown a correlation between pretransplant conditioning intensity, intestinal barrier loss, and graft-versus-host disease (GVHD) severity. However, because irradiation and other forms of pretransplant conditioning have pleiotropic effects, the precise role of intestinal barrier loss in GVHD pathogenesis remains unclear. We developed GVHD models that allowed us to isolate the specific contributions of distinct pretransplant variables. Intestinal damage was required for the induction of minor mismatch [major histocompatibility complex (MHC)-matched] GVHD, but was not necessary for major mismatch GVHD, demonstrating fundamental pathogenic distinctions between these forms of disease. Moreover, recipient natural killer (NK) cells prevented minor mismatch GVHD by limiting expansion and target organ infiltration of alloreactive T cells via a perforin-dependent mechanism, revealing an immunoregulatory function of MHC-matched recipient NK cells in GVHD. Minor mismatch GVHD required MyD88-mediated Toll-like receptor 4 (TLR4) signaling on donor cells, and intestinal damage could be bypassed by parenteral lipopolysaccharide (LPS) administration, indicating a critical role for the influx of bacterial components triggered by intestinal barrier loss. In all, the data demonstrate that pretransplant conditioning plays a dual role in promoting minor mismatch GVHD by both depleting recipient NK cells and inducing intestinal barrier loss.


Assuntos
Doença Enxerto-Hospedeiro/metabolismo , Células Matadoras Naturais/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Animais , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Lipopolissacarídeos , Camundongos , Camundongos Mutantes , Receptor 4 Toll-Like/metabolismo
17.
Arthritis Rheum ; 65(11): 2847-56, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23840022

RESUMO

OBJECTIVE: In the K/BxN mouse model of rheumatoid arthritis, T cells reactive for the self antigen glucose-6-phosphate isomerase (GPI) escape negative selection even though GPI expression is ubiquitous. We sought to determine whether insufficient GPI presentation could account for the failure of negative selection and for the development of arthritis. METHODS: To increase the antigen presentation of GPI, we generated transgenic mice expressing a membrane-bound form of GPI (mGPI) and crossed them with K/BxN mice. A monoclonal antibody specific for the α-chain of the KRN T cell receptor was generated to examine the fate of GPI-specific T cells. RESULTS: The mGPI-transgenic mice presented GPI more efficiently and showed a dramatic increase in negative selection and an inhibition of arthritis. Interestingly, thymic negative selection remained incomplete in these mice, and the escaped autoreactive T cells were anergic in the peripheral lymphoid organs, suggesting that enhanced antigen presentation also induces peripheral tolerance. Despite this apparent tolerance induction toward GPI, these mice developed a chronic wasting disease, characterized by colonic inflammation with epithelial dysplasia, as well as a dramatic reduction in Treg cells. CONCLUSION: These data indicate that insufficient autoantigen expression or presentation results in defects of both central and peripheral tolerance in the K/BxN mice. Our findings also support the idea that insufficient autoantigen levels may underlie the development of autoimmunity.


Assuntos
Apresentação de Antígeno/imunologia , Artrite Reumatoide/imunologia , Autoantígenos/imunologia , Glucose-6-Fosfato Isomerase/imunologia , Tolerância Imunológica/imunologia , Animais , Anticorpos Monoclonais/imunologia , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Citocinas/genética , Citocinas/imunologia , Modelos Animais de Doenças , Glucose-6-Fosfato Isomerase/genética , Camundongos , Camundongos Transgênicos , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia
18.
Cancer Res ; 64(15): 5127-31, 2004 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-15289315

RESUMO

KIT expression is a key diagnostic feature of gastrointestinal stromal tumors (GISTs), and virtually all of the GISTs express oncogenic forms of the KIT or PDGFRA receptor tyrosine kinase proteins, which serve as therapeutic targets of imatinib mesylate (Gleevec; Novartis, Basel, Switzerland). However, KIT expression can be low in PDGFRA-mutant GISTs, increasing the likelihood of misdiagnosis as other types of sarcoma. We report that the signaling intermediate protein kinase C theta (PKCtheta) is a diagnostic marker in GISTs, including those that lack KIT expression and/or contain PDGFRA mutations. PKCtheta is strongly activated in most GISTs and hence may serve, along with KIT/PDGFRA, as a novel therapeutic target.


Assuntos
Neoplasias Gastrointestinais/metabolismo , Regulação Neoplásica da Expressão Gênica , Isoenzimas/metabolismo , Proteínas Oncogênicas/genética , Proteína Quinase C/metabolismo , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Células Estromais/metabolismo , Ativação Enzimática , Neoplasias Gastrointestinais/patologia , Humanos , Técnicas Imunoenzimáticas , Mutação , Proteínas Oncogênicas/metabolismo , Fosforilação , Proteína Quinase C-theta , Proteínas Proto-Oncogênicas c-kit , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Células Estromais/patologia , Dedos de Zinco
19.
Oncogene ; 23(22): 3999-4006, 2004 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-15007386

RESUMO

Most gastrointestinal stromal tumors (GISTs) express constitutively activated forms of the KIT receptor tyrosine kinase protein, resulting from oncogenic mutations in the extracellular, juxtamembrane, or kinase domains. KIT oncoproteins are detected early in GIST tumorigenesis, and most GIST patients respond well to treatment with the KIT kinase inhibitor imatinib mesylate (STI571, Gleevec). However, GISTs can develop resistance to imatinib, and additional therapeutic strategies are needed. Little is known about oncogenic KIT signal transduction in GISTs, and whether the type of KIT mutation accounts for selective activation of downstream signaling intermediates. We therefore evaluated KIT downstream signaling profiles in 15 primary GISTs with mutations in KIT exons 9, 11, 13, and 17, and in two human GIST cell lines. All GISTs showed constitutive phosphorylation at KIT tyrosine residues Y703 and Y721. Additionally, most GISTs showed activation of MAPK p42/44, AKT, S6K, STAT1, and STAT3. STAT5 and JNK were not demonstrably activated in any GIST. Using GIST in vitro models, we showed that activation of MAPK p42/44, AKT, and S6K was KIT dependent, whereas STAT1 and STAT3 phosphorylation was only partially dependent on KIT activation. Correlation of activated signaling pathways with the type of KIT mutation revealed low levels of AKT phosphorylation in exon 9 mutant GISTs in contrast to a subset of GISTs with exon 11 mutations. However, additional factors are likely to modify the engagement of signaling pathways in GISTs as suggested by the fact that four GISTs with identical KIT exon 9 mutations had differential activation of MAPK p42/44 and STAT proteins. In summary, in this first report on KIT signal transduction in primary GISTs and GIST cell lines, we identified pathways that are constitutively activated in a KIT-dependent manner and therefore warrant further study as molecular targets in GISTs.


Assuntos
Neoplasias Gastrointestinais/metabolismo , Proteínas Oncogênicas/metabolismo , Transdução de Sinais/fisiologia , Apoptose/fisiologia , Divisão Celular/fisiologia , Feminino , Humanos , Masculino , Proteínas Proto-Oncogênicas c-kit , Células Estromais/citologia , Células Estromais/metabolismo
20.
Cancer Res ; 64(6): 1920-3, 2004 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15026324

RESUMO

Aneurysmal bone cyst (ABC) is a locally aggressive osseous lesion that typically occurs during the first two decades of life. ABC was regarded historically as a nonneoplastic process, but recent cytogenetic data have shown clonal rearrangements of chromosomal bands 16q22 and 17p13, indicating a neoplastic basis in at least some ABCs. Herein we show that a recurring ABC chromosomal translocation t(16;17)(q22;p13) creates a fusion gene in which the osteoblast cadherin 11 gene (CDH11) promoter region on 16q22 is juxtaposed to the entire ubiquitin-specific protease USP6 (Tre2) coding sequence on 17p13. CDH11-USP6 fusion transcripts were demonstrated only in ABC with t(16;17) but other ABCs had CDH11 or USP6 rearrangements resulting from alternate cytogenetic mechanisms. CDH11 is expressed strongly in bone, and our findings implicate a novel oncogenic mechanism in which deregulated USP6 transcription results from juxtaposition to the highly active CDH11 promoter.


Assuntos
Cistos Ósseos Aneurismáticos/genética , Caderinas/genética , Endopeptidases/genética , Proteínas de Fusão Oncogênica/genética , Proteínas Oncogênicas/genética , Translocação Genética , Adolescente , Cistos Ósseos Aneurismáticos/diagnóstico , Criança , Cromossomos Humanos Par 16 , Cromossomos Humanos Par 17 , Feminino , Rearranjo Gênico , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas , Ubiquitina Tiolesterase
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