Genetic screening and molecular characterization of MET alterations in non-small cell lung cancer

Purpose: Aberrant activation of MET as a result of exon 14-skipping (METex14) mutations or gene amplification is an oncogenic mechanism in non-small cell lung carcinoma (NSCLC) and a potential therapeutic target. The purpose of this study was to characterize MET alterations in a cohort of NSCLC patients treated with surgery. Methods and patients: 157 NSCLCs of various histopathologies, including pulmonary sarcomatoid carcinomas (PSC), were tested for MET alterations. METex14 mutations, MET copy number alterations and the levels of MET protein were determined by Sanger sequencing, fluorescence in situ hybridization and immunohistochemistry, respectively. Concurrent alterations of other important cancer genes and immunostaining of the downstream effector, phopho-S6, were also determined. Results: METex14 mutations and MET amplification were detected in seven tumors. MET genetic alterations were found predominantly in the lung adenocarcinoma (ADC) and PSC histopathologies. High levels of MET protein were found in most MET-amplified tumors, but not in all METex14-mutated tumors. Strong phopho-S6 staining was observed in about half of the MET-activated tumors. One tumor with METex14 exhibited concurrent ERBB2 amplification. Conclusions: MET activation, by either METex14 mutations or amplification, is characteristic of a subset of early stage NSCLCs and may coexist with ERBB2 amplification. This may have potential therapeutic implications. The presence of METex14 mutations was associated with low levels of MET protein, which may limit the use of total MET immunostaining as a marker for preselecting patients for MET-targeted therapies

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Targeted delivery of HGF to the skeletal muscle improves glucose homeostasis in diet-induced obese mice

Hepatocyte growth factor (HGF) is a cytokine that increases glucose transport ex vivo in skeletal muscle. The aim of this work was to decipher the impact of whether conditional overexpression of HGF in vivo could improve glucose homeostasis and insulin sensitivity in mouse skeletal muscle. Following tetracyclin administration, muscle HGF levels were augmented threefold in transgenic mice (SK-HGF) compared to control mice without altering plasma HGF levels. In conditions of normal diet, SK-HGF mice showed no differences in body weight, plasma triglycerides, blood glucose, plasma insulin and glucose tolerance compared to control mice. Importantly, obese SK-HGF mice exhibited improved whole-body glucose tolerance independently of changes in body weight or plasma triglyceride levels compared to control mice. This effect on glucose homeostasis was associated with significantly higher (∼80 %) levels of phosphorylated protein kinase B in muscles from SK-HGF mice compared to control mice. In conclusion, muscle expression of HGF counteracts obesity-mediated muscle insulin resistance and improves glucose tolerance in mice

The inmunohistochemical expression of c-Met is an independent predictor of survival in patients with lioblastoma multiforme

BACKGROUND AND AIMS: Because the outcome of glioblastoma multiforme (GBM) remains dismal, there is an urgent need for a better molecular characterization of this malignancy. The aim of this prospective study was to investigate the prognostic impact of the expression of c-mesenchymal-epithelial transition (c-Met) a receptor tyrosine kinase implicated in expression growth, survival, motility/migration, and invasion in GMB patients managed according to the established diagnostic and therapeutic protocols. METHODS: Between May 2003 and March 2011, a total of 69 patients (33 males and 36 females; mean age: 52.2 ± 12.9 years, age range: 23-81 years) referred to our Department for the surgical removal of GBM were evaluated immunohistochemically for c-Met expression. Progression-free survival (PFS) and overall survival (OS) served as the main outcome measures. RESULTS: Compared with c-Met- subjects (n = 38), c-Met+ subjects (n = 31) had both a significantly lower OS (15.3 ± 2.3 vs. 22.6 ± 2.5 months, respectively, p < 0.01) and PFS (12.3 ± 2.1 vs. 19.1 ± 2.6 months, respectively, p < 0.05). After allowance for potential confounders, multivariate Cox regression analysis identified c-Met+ as an independent predictor of both OS (hazard ratio = 1.7; 95 % confidence interval = 1.2-1.9, p < 0.01) and PFS (hazard ratio = 1.6; 95 % confidence interval = 1.1-2.3, p < 0.05). CONCLUSIONS: Our findings suggest that c-Met immunohistochemical expression is an independent predictor of outcomes in patients with GBM treated by standard of care (AU)

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Clinical and molecular prognostic prognostic predictors of malignant peripheral nerve sheath tumor

OBJECTIVE: Malignant peripheral nerve sheath tumors (MPNST) are relatively rare sarcomas and poorly understood. We sought to find clinicopathological and molecular predictors of survival for Chinese MPNST patients. METHODS: Clinical information from 146 MPNST patients treated in the Tianjin Medical University Cancer Institute and Hospital was collected and 56 cases of formalin-fixed and paraffin-embedded tissues were available for immunohistochemical examination of expression of hepatocyte growth factor receptor (c-MET), E3 ubiquitin-protein ligase Mdm2 (MDM2), and TP53. RESULTS: The 5-year tumor-free survival rate was 24 % and the median tumor-free survival time was 25.64 months. The 5-year overall survival rate was 57 % and the median overall survival time was 132.57 months. The expression patterns of c-MET, TP53, and MDM2 were heterogeneous with total positivity rates of 82.1 % (46/56), 55.4 % (31/56), and 73.2 % (41/56), respectively. The univariate analysis not only showed that tumor size, Neurofibromin 1 (NF1) status, the American Joint Committee on Cancer (AJCC) stage, surgery, MDM2 expression, and TP53 expression had significant correlation with the tumor-free survival, but also demonstrated that radiotherapy, chemotherapy, tumor size, and NF1 status had significant correlation with the overall survival. Even though multivariate analysis found no independent prognostic predictor of MPNST, tumor size and NF1 status had significant correlation with the tumor-free survival and overall survival of MPNST patients. CONCLUSIONS: With this, the largest documented Chinese cohort, our data supply powerful Chinese evidence of the prognostic role of tumor size and NF1 status in MPNST (AU)

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MET and VEGF: synergistic targets in castration-resistant prostate cancer

Recent advances in the treatment of prostate cancer have resulted in improved outcomes, including longer survival, but new options are needed for treating patients with castration-resistant disease, particularly in the presence of bone metastasis. Data from preclinical models and clinical biomarker studies indicate that antiangiogenic agents should be a promising treatment for this patient population, and multiple agents in this class have demonstrated activity in early-stage clinical trials. Pivotal trials in prostate cancer with agents targeting vascular endothelial growth factor (VEGF) signalling have resulted in significant improvements in tumour response and progression-free survival. However, overall survival was not significantly improved. Recent preclinical studies suggest that the limited impact on overall survival may result from the development of evasive resistance after inhibition of angiogenesis, possibly through upregulation of MET (hepatocyte growth factor receptor) signalling. MET plays important roles in angiogenesis, tumour cell invasion and bone metastasis, all of which are key factors in castration-resistant prostate cancer. Inhibition of both the MET and VEGF pathways may improve the efficacy of angiogenesis inhibitors in prostate cancer (AU)

C-MET as a new therapeutic target for the development of novel anticancer drugs

MET is a tyrosine kinase receptor that, upon binding of its natural ligand, the hepatocyte growth factor (HGF), is phosphorylated and subsequently activates different signalling pathways involved in proliferation, motility, migration and invasion. MET has been found to be aberrantly activated in human cancer via mutation, amplification or protein overexpression. MET expression and activation have been associated with prognosis in a number of tumour types and predict response to MET inhibitors in preclinical models. Here we review the HGF/MET signalling pathway, its role in human cancer and the different inhibitory strategies that have been developed for therapeutic use (AU)

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Cáncer de riñón hereditario / Hereditary renal cancer

El cáncer de riñón es la décima causa más común de muerte por cáncer. Esta revisión analiza las características de los síndromes hereditarios más frecuentes asociados a un subtipo histológico de tumor renal específico, su prevalencia y penetrancia, test genéticos disponibles y programas de cribado/detección precoz y tratamiento recomendados. En el síndrome de Von Hippel-Lindau un 40% de los pacientes desarrollan carcinoma renal de células claras bilateral y multifocal. También son frecuentes el hemangioblastoma del SNC o retina, feocromocitomas y tumores del saco endolinfático. Se han descrito cuatro fenotipos clásicos de VHL en función de la mutación y un diferente riesgo de feocromocitoma o carcinoma de células renales. Se puede realizar test genético de diagnóstico de confirmación, diagnóstico prenatal o preimplantación. El cáncer papilar renal hereditario tiene múltiples carcinomas papilares bilaterales de subtipo histológico 1. El gen asociado es el proto-oncogen c-met. El síndrome de Birt-Hogg-Dubé por mutaciones en el gen FLCN combina múltiples tumores renales bilaterales de tipo oncocitoma, carcinoma cromófobo, tumor híbrido oncocítico y una minoría carcinoma de células claras renales. Se asocia a fibrofoliculomas cutáneos, quistes de pulmón y neumotórax espontáneo. Histológicamente, hay lesiones iniciales de oncocitosis o híbridos oncocíticos excepcionales fuera del síndrome hereditario. La leiomiomatosis hereditaria y cáncer de células renales por mutaciones del gen fumarato hidratasa tiene en un 15%de los pacientes un agresivo carcinoma papilar tipo 2, en un 75% leiomiomas cutáneos múltiples y en 100% leiomiomas uterinos. En el estudio histopatológico se observan unos macronúcleolos eosinófilos característicos. La Esclerosis tuberosa es uno de los síndromes hereditarios más frecuentes asociado a angiomiolipoma (70% de afectados),quistes renales, oncocitoma o carcinoma renal de células claras (AU)

Kidney cancer is the tenth most common cause of cancer death. There are a growing number of genes known to be associated with an increased risk of specific types of kidney cancer. People with Von Hippel-Lindau syndrome have about a 40% risk of developing multiple bilateral clear cell kidney cancers. They can also develop retinal and brain hemangioblastoma, kidneys or pancreas cysts, pheochromocytoma and endolymphatic sac tumor. Four phenotypes with different renal cancer and pheocromocitoma risk have been described depending on the germline mutation. Hereditary papillary renal cell carcinoma syndrome has type 1 papillary renal cell carcinomas associated with protooncogenec-MET germline mutations. Birt-Hogg-Dubé syndrome has FLCN gene mutations associated with fibrofolliculomas, lung cysts with a high risk for spontaneous pneumothorax, and a 15% to 30% risk of kidney cancer (most classified as chromophobe carcinoma, oncocytoma or oncocytic hybrid, but clear cell and papillary kidney cancers have also been reported). Histopathological findings such as oncocytosis and oncocytic hybrids are very unusual outside the syndrome. Hereditary leiomyomatosis and renal cell cancer syndrome shows mutations of Fumarate hydratase gene and cutaneous leiomyomata in 76% of affected individuals, uterine leiomyomata in 100% of females, and unilateral, solitary, and aggressive papillary renal cancer in 10 to 16% of patients. A specific histopathological change is eosinophilic prominent nucleoli with a perinucleolar halo. Tuberous sclerosis complex is one of the most prevalent (1/5.800) hereditary syndromes where renal disease is the second leading cause of death, associated with angiomyolipomas (70%), renal cysts, oncocytomas or clear cell cancer (AU)