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Mast cell tumours (MCTs) are a common skin tumour in cats, but there is currently no histological grading system or reliable prognostic marker for this species (unlike the situation for dogs). This study utilized a set of 71 feline cutaneous MCTs with known clinical outcomes to assess the potential of various prognostic markers, including the cellular proliferation marker minichromosome maintenance protein (MCM)-7, mitotic index and various KIT labelling characteristics, including KIT positivity, KIT labelling pattern and KIT immunoreactivity score (IS). Of the factors studied, the mitotic index and the KIT labelling pattern were the only features associated significantly with survival times, while the proliferation marker MCM7 and the KIT IS were not. The study also highlights the variability of KIT labelling characteristics between tumours, which may prevent use of this marker as a diagnostic and prognostic tool., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Thymic dendritic cells (TDCs) are a type of dendritic cell (DC) in the thymus, which can enhance the proliferation of thymic T lymphocytes, regulate negative selection and induce central tolerance through autoantigen presentation. However, further investigations using TDCs has been restricted due to insufficient numbers. Therefore, an effective expansion method for TDCs in vitro is urgently required to further examine their biological characteristics. In the present study, a novel system was established using fetal thymus organ culture (FTOC) and a hanging drop culture system in the presence of fms‑like tyrosine kinase 3 ligand (Flt3L), termed the Flt3L/FTOC system. TDCs were successfully generated and expanded from CD117+ bone marrow hematopoietic progenitor cells. Conventional DCs (cDCs; CD11c+B220‑ DCs) and plasmacytoid DCs (pDCs; CD11c+B220+ DCs) were found in the TDCs generated using the Flt3L/FTOC system. These cells exhibited the specific morphological features of DCs, which were confirmed using Giemsa staining. Furthermore, the cytokine and surface marker profiles were also analyzed. Higher expression levels of interferon‑α and interleukin‑12 were observed in the pDCs, compared with the cDCs, and higher expression levels of toll‑like receptor (TLR)7 and TLR9 were found in the pDCs than in the cDCs. In addition, the Flt3L/FTOC‑derived TDCs also exhibited the ability to stimulate the allogenic T cell response. In conclusion, a novel in vitro culture system of thymic cDCs and pDCs using Flt3L was established, and this may provide a methodological basis for understanding the properties of TDCs.

Objective: The pathogenesis of abdominal aortic aneurysm (AAA) formation includes inflammation, vascular smooth muscle cell apoptosis, extracellular matrix degradation, and oxidative stress. That multipotent stem cells have an important role in cardiovascular health and disease has been well established, but the role of stem cells in aortic structural deterioration is poorly defined. We sought to describe the presence of stem cells in human AAA tissue and also investigated the differentiation of stem cells within the aneurysmal aorta., Methods: Infrarenal aortic wall specimens were collected from patients (n = 7) undergoing open AAA surgical repair. Nonaneurysmal infrarenal aortic control samples (n = 4) were collected at autopsies. Using immunohistochemistry, we compared the abundance of Stro1-positive ((+)), c-kit(+), and CD34(+) cells in aortic tissue. Using double-immunofluorescence staining, we evaluated stem cell differentiation into smooth muscle cells (SM22), fibroblasts (FSP1), and macrophages (CD68). We then investigated the colocalization of CD68(+) cells with the cellular marker of proliferation Ki67., Results: The media and adventitia of infrarenal AAA samples both demonstrated a significantly greater number of c-kit(+) and CD34(+) cells compared with matched control nonaneurysmal aortic tissues; however, the abundance of Stro1(+) cells was not significantly different between the groups. Using double-immunofluorescence staining, we identified that AAA stem cells express the macrophage marker CD68 but not the smooth muscle cell marker SM22 or the fibroblast marker FSP1. CD68(+) cells within the aortic wall colocalized with the cellular marker of proliferation Ki67., Conclusions: Stem cells are significantly elevated in infrarenal AAA tissue compared with matched control aortic tissue. Our data also demonstrate that AAA stem cells express macrophage surface antigens but not smooth muscle cell or fibroblast markers. Furthermore, CD68(+) cells within the aortic wall colocalized with the cellular marker of proliferation Ki67. These finding suggest an inflammatory/immune role of stem cells during AAA pathogenesis and raise the possibility of localized replenishment therapy within the aneurysm wall., (Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Mammary phyllodes tumours (PT) are rare biphasic neoplasms but have important clinical significance. Both epithelial and stromal components participate in PT development. Despite a number of studies on stromal c-kit in PT, little is known about the role of its epithelial expression., Objective: To further evaluate the stromal and epithelial expression of c-kit in a cohort of patients with PT., Method and Results: Expression of c-kit in both epithelial and stromal components was examined and correlated with histological features in PT. Stromal c-kit expression was associated positively with stromal cellularity (median expression=10.0, 30.0 and 50.0 from mild to severe cellularity; p=0.019). Conversely, a significant negative trend between epithelial c-kit expression with stromal pleomorphism (median expression=55.0, 30.0 and 2.5 from mild to severe pleomorphism; p=0.043) and mitosis (median expression=70.0 and 20.0 for low and high mitosis respectively; p=0.003); and a trend of negative correlation with increased PT grade was found. Despite these reverse associations, epithelial and stromal c-kit expressions were positively correlated with each other. Notably, the correlation of stromal c-kit expression with malignant histological features appeared to be stronger in cases with low epithelial c-kit expression but not in those with high epithelial c-kit expression., Conclusions: This study demonstrated the association of epithelial c-kit expression with stromal histological features and stromal c-kit. Interestingly, epithelial c-kit expression affected the strength of the correlation of stromal c-kit with these histological features. These findings provide further evidence of the interaction between the epithelial and stromal components in PT., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Gastrointestinal stromal tumors (GISTs) develop from interstitial cells of Cajal (ICCs) mainly by activating mutations in the KIT or PDGFRA genes. Immunohistochemical analysis for KIT, DOG1, and PKC-θ is used for the diagnosis of GIST. Recently, ETV1 has been shown to be a lineage survival factor for ICCs and required for tumorigenesis of GIST. We investigated the diagnostic value of ETV1expression in GIST. On fresh-frozen tissue samples, RT-PCR analysis showed that ETV1 as well as KIT, DOG1, and PKC-θ are highly expressed in GISTs. On tissue microarrays containing 407 GISTs and 120 non-GIST mesenchymal tumors of GI tract, we performed RNA in situ hybridization (ISH) for ETV1 together with immunohistochemical analysis for KIT, DOG1, PKC-θ, CD133, and CD44. Overall, 387 (95 %) of GISTs were positive for ETV1, while KIT and DOG1 were positive in 381 (94 %) and 392 (96 %) cases, respectively, showing nearly identical overall sensitivity of ETV1, KIT, and DOG1 for GISTs. In addition, ETV1 expression was positively correlated with that of KIT. Notably, ETV1 was positive in 15 of 26 (58 %) KIT-negative GISTs and even positive in 2 cases of GIST negative for KIT and DOG1, whereas only 6 (5 %) non-GIST mesenchymal GI tumors expressed ETV1. We conclude that ETV1 is specifically expressed in the majority of GISTs, even in some KIT-negative cases, suggesting that ETV1 may be useful as ancillary marker in diagnostically difficult select cases of GIST.

Introduction: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Numerous studies have reported the association between GIST and other neoplasms., Objectives: The aim of this study was to investigate the possible association between GIST and other tumors in a genetically isolated population., Methods: A retrospective study was conducted of patients with GIST between 2002 and 2009 at our center. Epidemiological, pathological and family data in patients with GIST alone (group A) were compared with those in patients with GIST associated with other neoplasms (group B). A possible common genetic mechanism was investigated between GIST and associated malignancies by testing the detection of the immunohistochemical marker, CD117, in all tumors., Results: Twenty-two patients with GIST were identified, 10 in group A (45%) and 12 in group B (55%). In group B, the associated tumor was malignant in 6 patients (50%) and benign in another 6 (50%). Of the 22 patients with GIST, 8 (36%) had a family history of malignancies. Of these 8 patients, 7 (87.5%) were in group B (p=0.03) and 3 (37.5%) showed the same pathological type of neoplasm as their relatives. All GIST were positive for CD117 whereas associated malignancies were negative for this marker., Conclusion: We did not find immunohistochemical positivity for CD117 in malignancies associated with GIST. Given the special characteristics of the study population, the association between GIST and associated malignancies may be incidental., (Copyright © 2015 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.)

Merkel cell polyomavirus is of oncogenic significance in approximately 80% of Merkel cell carcinomas. Morphological subcategories of the tumor differ in regard to viral status, the rare combined type being uniformly virus negative and the predominant pure type being mainly virus positive. Indications that different biological subsets of the tumor exist led us to explore this diversity. In an Eastern Canadian cohort of cases (75 patients; mean age, 76 years [range, 43-91]; male/female ratio, 43:32; 51 [68%] pure and 24 [34%] combined tumors), we semiquantitatively compared the immunohistochemical expression of 3 cellular proteins (p53, Bcl-2, and c-kit) in pure versus combined groups. Viral status was known in a subset of cases. The significant overexpression of p53 in the combined group (mean [SD], 153.8 [117.8] versus 121.6 [77.9]; P = .01) and the increased epidermal expression of this protein (p53 patches) in the same group lend credence to a primary etiologic role for sun damage in these cases. Expression of Bcl-2 and c-kit did not differ significantly between the 2 morphological groups. A relative increase in c-kit expression was significantly associated with a virus-negative status (median [interquartile range], 100 [60-115] versus 70 [0-100]; P = .03). Emerging data reveal divergent biological pathways in Merkel cell carcinoma, each with a characteristic immunohistochemical profile. Virus-positive tumors (all pure) exhibit high retinoblastoma protein and low p53 expression, whereas virus-negative cases (few pure and all combined) show high p53 and relatively high c-kit expression. The potential biological implications of this dichotomy call for consistent stratification of these tumors in future studies., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: We aimed to assess the clinicopathological relevance and prognostic significance of expression of the hepatic progenitor cell markers keratin 19 (K19), epithelial cell adhesion molecule (EpCAM) and CD117 (c-KIT) in a White series of hepatocellular carcinoma (HCC)., Methods: We evaluated the immunohistochemical expression of K19, EpCAM and CD117 in 89 surgical specimens of HCC from Greek patients (mean age 66.7±11.3 years, male 75.2%) followed up for 39.6±25.3 months., Results: K19, EpCAM and CD117 expression was detected in tumour cells of 10.11, 15.38 and 3.7% HCCs, respectively. Female sex was correlated with EpCAM immunohistochemical expression (P=0.035), whereas no other significant relationship with clinicopathological parameters was observed. K19 positivity tended to be correlated with microvascular invasion (P=0.054). In univariate analysis, K19 positivity and microvascular invasion were found to be associated with decreased recurrence-free survival (P<0.001 and P=0.004, respectively) and overall survival (P=0.002 and P=0.029, respectively). EpCAM and CD117 positivity was not correlated with patient survival. In multivariate analysis, K19 positivity emerged as an independent predictor of recurrence-free survival (odds ratio=7.84, 95% confidence interval=2.658-22.912, P<0.001) and overall survival (odds ratio=3.845, 95% confidence interval=1.401-10.549, P=0.009)., Conclusion: Our study confirms the prognostic significance of K19 expression in Caucasian patients with HCCs, providing further evidence that it may be used to stratify HCC according to tumour aggressiveness.

The conventional polymerase chain reaction (PCR)/sequencing methods may be poorly suited for the detection of somatic mutations in canine mast cell tumour (MCT) samples owing to limited sensitivity. This study was aimed at establishing novel and more sensitive methods, assessing their limit of detection and comparing their sensitivity with conventional methods.Two different 'driver' somatic mutations of c-KIT, together with the wild-type counterparts, were cloned in plasmids to prepare standard samples with known concentrations of mutated alleles in a background of wild-type alleles; the plasmids standards were assayed using either conventional or novel, highly sensitive technique. Conventional PCR/sequencing showed a sensitivity of 50-20%. Conversely, all the novel methods obtained higher sensitivities allowed reaching as low as 2.5-1.2% of the mutated DNA.The study demonstrates that early conventional methods could likely have underestimated the prevalence of KIT mutations of MCTs, therefore affecting the assessment of their relevance in prognosis and tyrosine kinase inhibitor (TKI) treatment effectiveness., (© 2013 Blackwell Publishing Ltd.)

The development of decellularised scaffolds for small diameter vascular grafts is hampered by their limited patency, due to the lack of luminal cell coverage by endothelial cells (EC) and to the low tone of the vessel due to absence of a contractile smooth muscle cells (SMC). In this study, we identify a population of vascular progenitor c-Kit+/Sca-1- cells available in large numbers and derived from immuno-privileged embryonic stem cells (ESCs). We also define an efficient and controlled differentiation protocol yielding fully to differentiated ECs and SMCs in sufficient numbers to allow the repopulation of a tissue engineered vascular graft. When seeded ex vivo on a decellularised vessel, c-Kit+/Sca-1-derived cells recapitulated the native vessel structure and upon in vivo implantation in the mouse, markedly reduced neointima formation and mortality, restoring functional vascularisation. We showed that Krüppel-like transcription factor 4 (Klf4) regulates the choice of differentiation pathway of these cells through β-catenin activation and was itself regulated by the canonical Wnt pathway activator lithium chloride. Our data show that ESC-derived c-Kit+/Sca-1-cells can be differentiated through a Klf4/β-catenin dependent pathway and are a suitable source of vascular progenitors for the creation of superior tissue-engineered vessels from decellularised scaffolds., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Unraveling the fate specification of resident stem cells during lung regeneration is of clinical importance. It has been reported that c-kit(+) progenitor cells resident in the human lung regenerate epithelial lineages upon transplantation into injured mouse lung. Here we test the lineage potential of c-kit(+) cells by inducible genetic lineage tracing. We find that c-kit(+) cells do not contribute to lung epithelium during homeostasis and repair, and instead maintain a vascular endothelial cell fate. These findings call attention to the clinical application of c-kit(+) stem cells as lung epithelial progenitors for the treatment of pulmonary disease.

Purpose: Despite the successful use of targeted and molecular therapies in other cancers, little progress has been made in the management of testicular germ cell tumors (TGCTs). c-kit (CD 117) is a good target for cancer treatment and possesses an impressive role in the current oncological practice. We aimed to evaluate c-kit expression in early stage TGCTs as a prognostic factor., Methods: Patients with TGCTs who were referred to the Medical Oncology Clinic and underwent curative surgical operation were included in our study before starting chemo- therapy. Immunohistochemistry was performed on formalin-fixed and paraffin-embedded three-micrometer thick sections with CD 117 Rabbit Anti c-kit in vitro gene kit. Biochemically, we utilized AFP and β-HCG Immunlite 2000 device with solid phase chemiluminescent immunometric method, and LDH Roche models with the DP-standardized UV method. AFP 0-15 ng/ml, β-HCG < 0.1 mlu/ml and LDH 240-480 mg/dl were considered as normal values., Results: Sixty-five patients were included in our study. Forty-one (63%) patients had non-seminoma tumors (NSGCTs) and 24 (37%) had seminoma. Statistically significant c-kit expression was found in patients with seminoma (p<0.0001). There was no difference between negative or positive c-kit expression in terms of clinicopathological characteristics, including preoperative serum levels of AFP, β-HCG, LDH, lymph node involvement, distant metastasis, and IGCCCG risk classification. No correlation was found between these parameters and 5-year progression free survival (PFS) rate except for tumor stage, presence of lymph node metastasis and IGCCCG score (p=0.001, p=0.04, and p=0.0001, respectively). Five-year PFS rate of patients with positive CD 117 was 72.2% (95% CI, 54.6-89.8), and 56.6% (95% CI, 31.2-82.1) for those without CD 117 expression involvement (p=0.12)., Conclusion: So far, there has been no significant breakthrough in the treatment of cisplatin-refractory TGCTs in the era of targeted therapies. No prognostic importance of c-kit expression has been found in our study. However, we believe that c-kit expression, in numerical terms, can be considered as a good prognostic factor for patients with TGCTs. The fact that all seminoma cases displayed positive c-kit expression is what we think has driven this result.

We characterized recently identified event clusters in systemic mastocytosis (SM) by calculating the coefficient of variation (CV, %) of CD117 and side scatter (SSC), based on the mean fluorescence intensity of mast cells using flow cytometry. Seventy-five samples were from patients with SM and 124 samples from patients negative for SM (non-SM). Discrete cluster formation seen in 50 cases correlated with significantly lower CV for SSC (46.1% vs. 61.0%, p < 0.0001) and CD117 (64.5% vs. 80.5%, p < 0.0001) for SM vs. non-SM samples. A combined CVCD117 + SSC of < 125 showed a sensitivity of 80% and specificity of 80% for SM with PPV of 67% and NPV of 80%. Probability scores of having SM, generated based on CVs for SSC and CD117, were significantly higher in patients with SM than non-SM (0.55 vs. 0.17, respectively; p < 0.001). Flow cytometric-based quantitative analysis of event clustering is a useful approach for diagnosing and monitoring patients with SM.

Recent studies have shown that mesenchymal stem cells (MSCs), under appropriate conditions, can differentiate into cell types including germ cells (GCs). These studies also show that MSCs without any induction express some GC-specific genes innately. Moreover, one report suggests that female MSCs have a greater tendency to differentiate into female instead of male GCs. Therefore, for the first time, this study attempts to assay and determine the differences between the expression levels of some important GC-specific genes (Stra8, Vasa, Dazl, Stella, Piwil2, Oct4, Fragilis, Rnf17 and c-Kit) in male and female bone marrow (BM)-MSCs of rats. BM sampling of the rate was performed by a newly established method. We cultured rat BM samples, then characterized male and female MSCs according to their adhesion onto the culture dish, their differentiation potential into bone, cartilage and fat cells, and phenotype analysis by flow cytometry. The expression of GC-specific genes and their expression levels were evaluated with reverse transcription polymerase chain reaction (RT-PCR) and real-time RT-PCR. Our results showed that Dazl and Rnf17 did not express in the cells. The majority of examined genes, except Piwil2, expressed at almost the same levels in male and female MSCs. Piwil2 had higher expression in male MSCs which was probably related to the more prominent role of Piwil2 in the male GC development process. Male BM-MSCs appeared more prone to differentiate into male rather than female GCs. Additional research should be performed to determine the exact role of different genes in the male and female GC development process.

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract that are most commonly found in the stomach. Although GISTs can spread to the liver and peritoneum, metastasis to the skeletal muscle is very rare and only four cases have previously been reported. These cases involved concurrent skeletal metastases of primary GISTs or liver metastases. Here, we report the first case of a distant recurrence in the brachialis muscle after complete remission of an extra-luminal gastric GIST following a wedge resection of the stomach, omental excision, and adjuvant imatinib therapy for one year. Ten months after therapy completion, the patient presented with swelling and tenderness in the left arm. Magnetic resonance imaging revealed a large mass in the brachialis muscle, which showed positivity for c-kit and CD34 upon pathologic examination. This is the first reported case of a solitary distant recurrence of a GIST in the muscle after complete remission had been achieved.

Cardiovascular disease is the leading cause of morbidity and mortality in the developed world. Although ongoing therapeutic strategies ameliorate symptoms and prolong life for patients with cardiovascular diseases, they do not solve the critical issue related to the loss of cardiac tissue. Accordingly, stem/progenitor cell therapy has emerged as a paramount approach for cardiac repair and regeneration. In this regard, c-kit(+) cells have animated much interest and controversy. These cells are self-renewing, clonogenic, and multipotent and display a noteworthy potential to differentiate into all cardiovascular lineages. However, their functional contribution to cardiomyocyte turnover is one of the centrally debated issues concerning their regenerative potential. Regardless, plentiful preclinical and clinical studies have been conducted which provide evidence for the capacity of c-kit(+) cells to improve cardiac function. The purpose of this review is to give a comprehensive, impartial, critical description and evaluation of the literature on c-kit(+) cells from bench to bedside in order to address their true potential, benefits and controversies.

To clarify the status of gene mutation and activation of growth signal in melanoma of Japanese patients in vivo, we analyzed the mutation of BRAF exon 15, NRAS exon 2, and KIT exons 9, 11, 13, 17 and 18 in melanoma cells obtained by laser capture microdissection, and performed direct sequencing in 20 cases of acral lentiginous melanoma (ALM) and 17 cases of superficial spreading melanoma (SSM). In the study of the mutation of BRAF, pyrosequencing was also done. To examine the cell proliferation signaling, immunohistochemistry for phosphorylated extracellular signal-regulated kinase (pERK), phosphorylated AKT (phosphorylated AKT) and c-KIT was done. The mutation of BRAF p.V600E was detected in 13 cases of ALM (65.0%) and 12 cases of SSM (70.6%). No NRAS mutation was found in all cases. The mutation in exons 9, 11, and 18 of KIT was detected in nine cases. The mutation of BRAF and KIT showed no correlation with clinical stage, lymph node metastasis, tumor thickness, ulceration and histology. pERK and pAKT was observed in small population of melanoma cells and there was no correlation with gene mutation. Our results indicate that the mutations of BRAF and KIT exist in Japanese melanoma patients, however, the cell growth signaling may be regulated by not only these mutated genes, but by other unknown regulatory factors, which may affect the prognosis of melanoma., (© 2015 Japanese Dermatological Association.)

Background: Mesenchymal Gastrointestinal (GI) tumours are heterogenous group of tumours. Prior to 2005, immunohistochemistry (IHC) was not used in diagnostic pathology to characterize these tumours at our centre., Objectives: To subclassify mesenchymal tumours in the GI tract and related locations into Gastrointestinal stromal tumour (GIST) and non-GIST tumours using specific IHC antibody markers., Methods: Formalin Fixed Paraffin Embedded tumour tissue over the period 1991- 2004 were retrieved, from the files and records of the Department of Pathology, University College Hospital, Ibadan, Nigeria. Haematoxylin and Eosin slides of such cases were reviewed. The IHC expressions of c-Kit, CD 34, α-smooth muscle actin, desmin and S-100 were evaluated in these tumours., Results: Based on morphology and IHC staining pattern, 24 of the 46 cases were identified as GIST by c-kit positivity. Nine of the cases were smooth muscle tumours (4- leiomyoma and 5- leiomyosarcoma), 8 cases of undifferentiated sarcomas, 4 cases of desmoid and one case of inflammatory myofibroblastic tumour. For GISTs: The male:female ratio is 1.2. The age range of the patients was 11-75 years with a mean age of 55.1 years.Tumour size ranged from 7-32 cm with an average of 19.8cm and average mitotic count of 20 per 50 high power field. The location of the GIST tumours were as follow- stomach- 9 cases (37.5% of the 24 GIST cases), colon and rectum -6 (25%), Abdominal cavity (omentum/ mesentery)- 6 (25%), retroperitoneum-2(8.3%), small intestine-1 (4.2%)., Conclusion: The use of IHC in this study has helped to segregate and distinguish GI mesenchymal tumours into different sub-types, majority being Gastrointestinal stromal tumours.

Rationale: The mechanism of functional restoration by stem cell therapy remains poorly understood. Novel manganese-enhanced MRI and bioluminescence reporter gene imaging were applied to follow myocardial viability and cell engraftment, respectively. Human-placenta-derived amniotic mesenchymal stem cells (AMCs) demonstrate unique immunoregulatory and precardiac properties. In this study, the restorative effects of 3 AMC-derived subpopulations were examined in a murine myocardial injury model: (1) unselected AMCs, (2) ckit(+)AMCs, and (3) AMC-derived induced pluripotent stem cells (MiPSCs)., Objective: To determine the differential restorative effects of the AMC-derived subpopulations in the murine myocardial injury model using multimodality imaging., Methods and Results: SCID (severe combined immunodeficiency) mice underwent left anterior descending artery ligation and were divided into 4 treatment arms: (1) normal saline control (n=14), (2) unselected AMCs (n=10), (3) ckit(+)AMCs (n=13), and (4) MiPSCs (n=11). Cardiac MRI assessed myocardial viability and left ventricular function, whereas bioluminescence imaging assessed stem cell engraftment during a 4-week period. Immunohistological labeling and reverse transcriptase polymerase chain reaction of the explanted myocardium were performed. The unselected AMC and ckit(+)AMC-treated mice demonstrated transient left ventricular functional improvement. However, the MiPSCs exhibited a significantly greater increase in left ventricular function compared with all the other groups during the entire 4-week period. Left ventricular functional improvement correlated with increased myocardial viability and sustained stem cell engraftment. The MiPSC-treated animals lacked any evidence of de novo cardiac differentiation., Conclusion: The functional restoration seen in MiPSCs was characterized by increased myocardial viability and sustained engraftment without de novo cardiac differentiation, indicating salvage of the injured myocardium., (© 2015 American Heart Association, Inc.)

Gastric carcinosarcomas are rare morphologically biphasic tumors, consisting of carcinoma and sarcoma components, with a poor clinical course. Here we report the case of a 70-year-old man with advanced Borrmann type III carcinosarcoma arising from the upper body of the stomach with extensive lymph node metastasis who underwent a total, but palliative, gastrectomy. Histology showed the tumor consisted of a biphasic structure of tubular adenocarcinoma and spindle cell sarcoma. Immunohistochemistry revealed sarcoma cells expressing c-kit (CD117) and CD34, which are criteria for gastrointestinal stromal tumors. Nine months after the surgical operation, tumor metastases had extended to the hepatohilar, retroperitoneal and mediastinal lymph nodes. Radiation therapy of 50 Gy markedly decreased the size of each of these nodes and reduced the risk of respiratory complications and jaundice. However, the patient died of respiratory failure due to bronchopneumonia with multiple lung metastases 22 mo after resection. Autopsy revealed severe necrosis in most of the lymph nodes with tumor metastases. Radiation therapy combined with gastrectomy should be considered to improve survival in patients with gastric carcinosarcomas that express c-kit.

Liver fibrosis is a wound-healing response which engages a variety of cell types to encapsulate injury. Telocyte (TC), a novel type of interstitial cell, has been identified in a variety of tissues and organs including liver. TCs have been reported to be reduced in fibrotic areas after myocardial infarction, human interstitial wall's fibrotic remodelling caused either by ulcerative colitis or Crohn's disease, and skin of systemic sclerosis. However, the role of TCs in human liver fibrosis remains unclear. Liver samples from human liver biopsy were collected. All samples were stained with Masson's trichrome to determine fibrosis. TCs were identified by several immunofluorescence stainings including double labelling for CD34 and c-kit/CD117, or vimentin, or PDGF Receptor-α, or β. We found that hepatic TCs were significantly decreased by 27%-60% in human liver fibrosis, suggesting that loss of TCs might lead to the altered organization of extracellular matrix and loss the control of fibroblast/myofibroblast activity and favour the genesis of fibrosis. Adding TCs might help to develop effective and targeted antifibrotic therapies for human liver fibrosis., (© 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Background: Mucosal melanomas (MM) represent a heterogeneous tumour population that exhibits site-specific molecular profiles., Aims: In a multicentre retrospective study, we investigated KIT aberrations in primary anorectal (AR) melanomas compared with melanoma metastatic to the gastrointestinal (GI) tract., Methods: Primary AR MM (n=31) and GI metastatic melanoma (n=27) were studied for KIT mutations on exons 11, 13, 17 and 18 by high-resolution melting analysis, direct sequencing and c-KIT expression by immunohistochemistry. Selected cases were also investigated for increased KIT gene copy number by fluorescent in situ hybridisation., Results: Functional KIT mutations were demonstrated in 11/31 (35.5%) of AR melanomas and in 1/26 (3.8%) of GI melanoma metastases (p=0.004). A significant difference emerged between primary and metastatic MM with regards to KIT-positive immunostaining (p=0.002). Immunohistochemical c-KIT protein overexpression did not correlate with KIT mutational status. Increased KIT copy number was demonstrated in 5/20 AR primary cases., Conclusions: The rate of functional mutations in KIT is significantly higher in AR MM than in GI metastatic melanoma. KIT protein overexpression does not correlate with KIT mutations and cannot be used for screening purposes. Recognising the molecular heterogeneity of MM helps to identify patients who require a different therapeutic approach., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Soft tissue tumors are rare tumors that show a heterogeneous structure; thus far, their molecular behavior has not been elucidated. The aim of our study was to define the relationship between microvessel density (MVD), evaluated with CD31, and other immunohistochemical markers, such as vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), CD34, maspin, DOG-1, and c-KIT. Immunostains were done in 55 cases consisting of benign and malignant tumors, such as liposarcomas, dermatofibrosarcomas, and tumors with histiocytic differentiation. Renal tubes were used as external control for VEGF, maspin, and DOG-1. Although DOG-1 is considered a specific marker for gastrointestinal tumors (GISTs), its positivity, correlated with c-KIT and VEGF immunoexpression, was also shown by dermatofibrosarcomas and tumors with histiocytic and lipomatous differentiation, suggesting its possible pro-angiogenic role. Maspin expression was observed in adipose tissue tumors only. Regarding angiogenesis, 31 of the 55 cases were VEGF-positive, such positivity being directly correlated with COX-2 and CD34 positivity as evaluated in the tumor cells and also with MVD. Although no significant differences in angiogenic activity were found between benign and malignant non-lipomatous tumors, the MVD was directly correlated with the histological type/grade of liposarcomas. Based on these aspects, we conclude that VEGF/COX-2-induced angiogenesis is specific for non-lipomatous tumors, whereas liposarcomas are dependent on the VEGF/maspin angiogenic pathway. The DOG-1/c-KIT/VEGF target may be used for further personalized therapy of soft tissue sarcomas. No data about DOG-1 and maspin positivity in liposarcomas have been published to date.

We performed an immunohistochemical (IHC) study to determine the follicular expression of growth differentiation factor 9 (GDF-9), anti-Müllerian hormone (AMH), Kit Ligand (KL), and c-Kit in squirrel monkey ovary. Ovarian tissue fragments from 4 squirrel monkeys were collected by laparotomy and processed for classical histology and IHC. Additionally, follicle development was assessed by Ki67 immunostaining to evaluate proliferative status of granulosa cells. A total of 4025 follicles were examined (1475 for classical histology and 2550 for immunohistochemistry). More than 80% of the evaluated follicles were morphologically normal. The GDF-9 protein was detectable in oocyte cytoplasm from primordial (100%), primary (99.1%), and secondary (100%) follicles. The AMH was not expressed in primordial follicles but just in few primary follicles (13.8%). On the other hand, it was highly expressed in granulosa cells from secondary follicles (67.9%). c-Kit, KL receptor, was found in the oolemma of primordial (100%), primary (100%), and secondary (100%) follicles. The KL expression was observed in oocytes and granulosa cells from primordial (94.9%), primary (91.6%) and secondary follicles (100%). Ki67 immunostaining was observed in granulosa cells from primary (5.7%) and secondary (54.8%) follicles but not in primordial follicles. In conclusion, we described the localization of GDF-9, KL, c-Kit, and Ki67 proteins and confirmed the presence of AMH protein in preantral follicles from squirrel monkey. Our results offer contribution for understanding of folliculogenesis in neotropical nonhuman primates. Moreover, these markers can be used to assess follicular viability and functionality after cryopreservation, transplantation, or in vitro culture of ovarian tissue., (© The Author(s) 2014.)

Extra gastrointestinal stromal tumors (EGIST) are reported in different sites and organs. This tumors are rare in gynecologic apparatus. Here the authors report an uterine unique tumor represented as intramural leiomyoma. Because of different treatment options, clinicians should be aware of this rare tumor which may be located in uterus and confused with a smooth muscle tumor.

Interstitial cells of Cajal (ICC) are mesenchymal cells that are distributed along the gastrointestinal tract and function as pacemaker cells or intermediary cells between nerves and smooth muscle cells. ICC express a receptor tyrosine kinase c-Kit, which is an established marker for ICC. The c-kit gene is allelic with the murine white-spotting locus (W), and some ICC subsets were reported to be missing in heterozygous mutant W/W(v) mice carrying W and W(v) mutated alleles. In this study, the characterization of interstitial cells in the subserosal layer of W/W(v) mice was analyzed by immunohistochemistry and electron microscopy. In the proximal and distal colon of W/W(v) mutant mice, no c-Kit-positive cells were detected in the subserosal layer by immunohistochemistry. By electron microscopy, the interstitial cells, which were characterized by the existence of caveolae, abundant mitochondria and gap junctions, were observed in the W/W(v) mutant colon. The morphological characteristics were comparable to those of the multipolar c-Kit positive ICC seen in the subserosa of proximal and distal colon of wild-type mice. Fibroblasts were also located in the same layers, but the morphology of the fibroblasts was distinguishable from that of ICC in wild type mice or of ICC-like cells in W/W(v) mutant mice. Collectively, it is concluded that c-Kit-negative interstitial cells showing a typical ICC ultrastructure exist in the proximal and distal colon of W/W(v) mutant mice.

In order to better understand the ovarian serous carcinogenic process with tubal origin, we investigated the expression of stem cell markers in premalignant tubal lesions (serous tubal intraepithelial carcinoma or STIC). We found an increased stem cell marker density in the normal fallopian tube followed by a high CD117 and a low ALDH and CD44 expression in STICs raising the question of the role of the stem cell markers in the serous carcinogenic process.

Background: Gastrointestinal cancers are among the leading causes of cancer-related deaths worldwide. In different tumor types, personalized systemic treatment strategies based upon biomarker-selection were established over the last years. Although there is a flood of targeted agents in clinical development, only a few targeted agents with a predictive biomarker could be established for the treatment of patients with gastrointestinal cancer patients so far., Summary: Currently, predictive biomarkers for gastrointestinal cancers include Her2 overexpression or amplification (gastroesophageal adenocarcinoma), c-Kit overexpression (gastrointestinal stromal tumors) and RAS wild-type (colorectal cancer). Selection of patients based on these biomarkers allows the efficient use of targeted agents. The presence of a BRAF mutation and/or high microsatellite instability is prognostic and rather a predictive marker in CRC. Promising candidate markers in advanced clinical development are MET amplification in gastroesophageal adenocarcinoma, Met overexpression and high AFP serum levels in hepatocellular carcinoma., Key Message: Biomarker-guided systemic treatment is established in a subset of patients with gastrointestinal cancer. Ongoing clinical trials and further advances in high-throughput technologies will hopefully result in more personalized systemic treatment strategies for these patients in the near future.

Although the stomach is the most common location for gastrointestinal stromal tumor (GIST) with co-primary tumors, the synchronous appearance of a poorly differentiated neuroendocrine carcinoma (NEC) and GIST in the stomach is extremely rare. To the best of our knowledge, this is the first case of gastric GIST coexisting with gastric NEC to be reported in the literature. The current study reports the case of a 71-year-old male with gastric poorly differentiated NEC and GIST discovered incidentally during surgical treatment of the NEC. Immunohistochemistry analysis showed that the NEC tumor cells were positive for CK (cytokeratin), CD57, synaptophysin, chromogranin, CD117 (KIT protein), Dog-1 (discovered on GIST-1 protein) and CD34. The synchronous GIST immunophenotype showed positivity for CD117, Dog-1 and CD34 (100%), whereas staining for CK, SMA, desmin and S100 was negative. Ki-67 labeling of proliferating cells was 90% in NEC and 1% in GIST. An accurate diagnosis was confirmed by immunohistochemical findings. Furthermore, genetic analysis using PCR direct sequencing identified no mutations in the KIT (exons 9, 11, 13 and 17) and PDGFRA (exons 12 and 18) genes. The patient developed lymph node metastases and underwent cisplatin-based chemotherapy after the operation. This is the first documented case of synchronous gastric GIST and NEC with the examination of protein expression and gene mutations in KIT and PDGFRA, which will help to further understand the etiology and pathogenesis of NEC coexisting with GIST in a gastric location.

Background: Various kinds of molecular targeted drugs to inhibit receptor tyrosine kinases (RTKs) have been recently developed. The relationship between the expression status of major RTKs and prognosis in gastric cancer remains unclear. We conducted a multicenter study to evaluate the prognostic impact of the expression of epidermal growth factor receptor (EGFR), c-Met, platelet-derived growth factor receptor (PDGFR), and c-Kit in gastric cancer., Methods: This study included 153 gastric cancer patients who underwent gastrectomy at 9 institutions between 2000 and 2006. Expression status of EGFR, c-Met, PDGFR, and c-Kit were evaluated with immunohistochemistry (IHC) centrally. Overall survival based on RTK expression status was statistically compared. Cox multivariate analysis was conducted to adjust for potentially confounding factors., Results: The positive rates for EGFR, c-Met, PDGFR, and c-Kit were 14.4, 24.8, 41.2, and 11.1 %, respectively. Significant interactions with expression status were observed for pathological N stage with EGFR; HER2-status with c-Met; tumor location, histology, and pathological N stage with PDGFR; and no examined variables with c-Kit. Concomitant HER2 positivity was observed for 0.7 % of tumors positive for EGFR, 3.9 % for c-Met, 4.6 % for PDGFR, and 1.3 % for c-Kit. There were some differences in overall survival between patients with or without RTK expression, but only c-Kit expression showed a significant survival difference in Cox multivariate analysis (P = 0.046)., Conclusions: Our multicenter study indicated that IHC expression of 4 RTKs had some prognostic impact and that c-Kit-positive status may be a significant indicator of good prognosis in gastric cancer patients.

The stem cell factor (SCF) receptor CD117 (c-kit), is widely used for identification of hematopoietic stem cells and cancer stem cells. Moreover, CD117 expression in carcinoma cells indicates a poor prognosis in a variety of cancers. However the potential expression in tumor microenvironment and the biological and clinical impact are currently not reported. The expression of CD117 was immunohistochemically evaluated in a serial of 242 epithelial ovarian cancer (EOC) cases. Thirty-eight out of 242 cases were CD117 positive in fibroblast-like stromal cells and 22 cases were positive in EOC cells. Four cases were both positive in fibroblast-like stromal cells and EOC cells for CD117. CD117 expression in fibroblast-like stromal cells in ovarian carcinoma was closely linked to advanced FIGO stage, poor differentiation grade and histological subtype (p<0.05), and it was significantly associated with poor overall survival (OS) and progression free survival (PFS) (Kaplan-Meier analysis; p<0.05, log-rank test). CD117 expression in ovarian carcinoma cells was not associated with these clinicopathological variables. The CD117 positive fibroblast-like stromal cells were all positive for mesenchymal stem/stromal cell (MSC) marker CD73 but negative for fibroblast markers fibroblast activation protein (FAP) and α smooth muscle actin (α-SMA), indicating that the CD117+/CD73+ fibroblast-like stromal cells are a subtype of mesenchymal stem cells in tumor stroma, although further characterization of these cells are needed. It is concluded herewith that the presence of CD117+/CD73+ fibroblast-like stromal cells in ovarian carcinoma is an unfavorable clinical outcome indication.

Desmoid tumors are benign fibroblastic neoplasms with no metastatic potential, but a propensity for local recurrence even after complete surgical resection. These lesions can develop at any site in the body, and commonly occur in the intra-abdominal area. Intra-abdominal desmoid tumors usually occur at the mesentery or retroperitoneum, and may morphologically mimic gastrointestinal stromal tumors (GISTs). Distinguishing between these tumors is important, because the therapies differ substantially, but is often difficult even with the use of CD117 staining. We herein report the cases of two patients with sporadic intra-abdominal desmoid tumors that were differentiated from GIST by immunohistological examination using beta-catenin and CD34. Desmoid tumors specifically express nuclear beta-catenin, and show no expression of CD34. We recommend staining for beta-catenin and CD34 when an intra-abdominal desmoid tumor is suspected.

Chagasic cardiomyopathy, resulting from infection with the parasite Trypanosoma cruzi, was discovered more than a century ago and remains an incurable disease. Due to the unique properties of mesenchymal stem cells (MSC) we hypothesized that these cells could have therapeutic potential for chagasic cardiomyopathy. Recently, our group pioneered use of nanoparticle-labeled MSC to correlate migration with its effect in an acute Chagas disease model. We expanded our investigation into a chronic model and performed more comprehensive assays. Infected mice were treated with nanoparticle-labeled MSC and their migration was correlated with alterations in heart morphology, metalloproteinase activity, and expression of several proteins. The vast majority of labeled MSC migrated to liver, lungs and spleen whereas a small number of cells migrated to chagasic hearts. Magnetic resonance imaging demonstrated that MSC therapy reduced heart dilatation. Additionally metalloproteinase activity was higher in heart and other organs of infected mice. Protein expression analyses revealed that connexin 43, laminin γ1, IL-10 and INF-γ were affected by the disease and recovered after cell therapy. Interestingly, MSC therapy led to upregulation of SDF-1 and c-kit in the hearts. The beneficial effect of MSC therapy in Chagas disease is likely due to an indirect action of the cells of the heart, rather than the incorporation of large numbers of stem cells into working myocardium., (Copyright © 2014. Published by Elsevier Masson SAS.)

Adequate management of phyllodes tumors of the breast (PTB) remains a challenge because of the difficulty in correctly establishing preoperative diagnosis. The aim of this study was to evaluate the usefulness of Ki-67, CD10, CD34, p53, CD117, and of the number of mast cells in the differential diagnosis of benign PTB and cellular fibroadenomas (CFs) as well as in the grading of PTB. Fifty-one primary PTB and 14 CFs were examined by immunohistochemistry.When evaluating CD117 expression, higher epithelial expression was present in CF as well as an increased number of mast cells in benign PTB. Stromal expression of Ki-67, CD10, CD34, and p53 were relevant to PTB grading, of which the first 3 showed significance in the distinction of benign and borderline PTB, as well as between benign and malignant PTB. P53 was relevant only for the discrimination between benign and malign PTB. None of the markers showed significance in distinguishing between borderline and malign PTB., (© The Author(s) 2014.)

A 69-year-old woman underwent 4 months of imatinib mesylate chemotherapy for a diagnosed gastrointestinal stromal tumor of the esophagus. This treatment was suspended because of its side effects and because radiological examinations showed that the tumor had not changed or had even increased slightly in size. Thus, we performed esophagectomy via left thoracotomy and removed a tumor that measured 18 × 17 × 10 cm. Immunohistochemical examination revealed positive reactions for c-kit and CD34, suggestive of a high-risk malignancy. The patient was discharged from hospital on postoperative day 30, and has remained well with no sign of tumor recurrence for more than 5 years, without adjuvant chemotherapy.

CD117 (C-kit) is thought to play an important role in tumourigenesis. There are limited data in the literature concerning C-kit expression in retinoblastoma. To date, no immunohistochemical studies have been performed to assess the possible association of C-kit with vascular endothelial growth factor (VEGF) in retinoblastoma. This study was designed to investigate C-kit and VEGF immunoexpression in retinoblastoma, their relationship with prognostic parameters as well as the correlation between them. A prospective immunohistochemical study was conducted on 56 retinoblastoma cases. Patients who had received preoperative chemotherapy were excluded. Positive C-kit and VEGF immunoreactivity was observed in 48.2% and 76.8% of retinoblastoma cases respectively. No C-kit immunostaining was seen in the adjacent uninvolved retina. However, VEGF expression was detected within its vasculature. Retinoblastomas with combined pattern of tumour growth revealed a highly significant positive C-kit expression (P = 0.002) compared to cases with endophytic or exophytic growths. Also, positive C-kit expression was statistically higher in cases with optic nerve invasion (P = 0.001) and choroidal invasion (P ≤ 0.01) compared to negative cases. A highly significant positive VEGF expression was detected in cases with optic nerve invasion (P = 0.013) compared to negative cases. Moreover, a highly significant positive correlation was detected between C-kit and VEGF expression (P = 0.006). C-kit is a feature of more aggressive retinoblastomas, with increased expression in tumours spreading beyond the retina. Moreover, VEGF is vastly expressed in retinoblastoma and is associated with optic nerve invasion. Both C-kit and VEGF may represent potential therapeutic targets for retinoblastomas.

Background: c-KIT/CD117 down-regulation has been described in papillary thyroid carcinoma (PTC). In this study, the authors investigated CD117 as an ancillary immunocytochemical test for PTC in fine-needle aspiration biopsy (FNAB)., Methods: The expression of CD117 was assessed in cytologic samples of histologically confirmed classic PTC (n = 35) and in a control group of benign thyroid nodules (BTNs) (n = 30) using immunocytochemistry. The corresponding PTCs and BTNs from surgical resection specimens also were evaluated immunohistochemically for CD117. The expression of CD117 was assessed semiquantitatively using a scoring system from 0 to 5 that combined the proportion and the intensity of staining., Results: The difference in immunoreactivity for CD117 between PTC and BTNs was highly significant both in FNAB samples and in the corresponding histology samples (P < .0001). On cytology, most PTCs (74%; n = 26) lacked immunoreactivity for CD117, and 9 samples (26%) had faint reactivity in <2% of tumor cells (score, 0). In contrast, all BTNs (100%; n = 30) were positive for CD117, and at least 50% of the cells (score, 2-4) were positive in 79% (n = 24) of BTNs. Results with corresponding histology were similar to the cytology results; most PTCs (89%; n = 31) lacked immunoreactivity for CD117, and 4 samples (11%) had faint reactivity in <2% of tumor cells. In contrast, all BTNs (n = 30) were variably positive for CD117 (score, 2-4). Normal follicular epithelium also was positive for CD117 (score, 2-4)., Conclusions: CD117 is expressed in both normal follicular epithelium and in BTNs. In contrast, expression of CD117 is absent or weak in PTC. These results suggest that CD117 may be useful as an ancillary marker for PTC., (© 2014 American Cancer Society.)

Background: Although several studies reported that distant metastasis occurs more frequently in the tumors of submandibular gland (SMG) than parotid gland (PG), why SMG tumors preferentially metastasize to distant organs is not fully understood. We aimed to identify the differential tumor microenvironment for distant metastasis and possible underlying mechanisms., Methods: We retrieved 27 cases of 1-4-cm-sized adenoid cystic carcinomas (ACCs) arising from the PG (n = 12) and SMG (n = 15). c-KIT, VEGF-R2, and CD31 staining were quantified by image-based analysis to define the positive expression or tumor-associated vessel areas in two representative sections per case. In addition, angiogenesis-related genomic expression profiling was carried out to explore the underlying mechanism, which was confirmed by RT-PCR and immunohistochemistry., Results: Earlier systemic dissemination within 2 years was detected exclusively in SMG ACCs (5/15). The area of tumor-associated blood vessels was larger in SMG ACCs than PG ACCs, and ACCs showing distant metastasis had greater blood vessel area than those without metastasis. Interestingly, normal SMG had more blood vessels per area than PG. Among angiogenesis-related signals, the level of IL-6 was significantly lower in SMG ACCs than PG ACCs. Moreover, IL-6 expression decreased significantly in SMG ACCs compared with that in normal SMG, whereas it was up-regulated in PG ACCs., Conclusion: ACCs in the SMG microenvironment have more abundant tumor-associated blood vessels than PG ACCs, which may explain the higher risk of distant metastasis from SMG tumors., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: CASTLE (Carcinoma showing thymus-like elements) is a rare malignant neoplasm of the thyroid resembling lymphoepithelioma-like and squamous cell carcinoma of the thymus with different biological behaviour and a better prognosis than anaplastic carcinoma of the thyroid., Methods: We retrospectively investigated 6 cases of this very rare neoplasm in order to investigate the mutational status of KRAS, EGFR, PDGFR-α and KIT, as well as the immunohistochemical expression pattern of CD117, EGFR and COX-2, and possibly find new therapeutic targets., Results: Diagnosis was confirmed by a moderate to strong expression of CD5, CD117 and CK5/6, whereas thyroglobulin, calcitonin and TTF-1 were negative in all cases. Tumors were also positive for COX-2 and in nearly all cases for EGFR. In four cases single nucleotide polymorphisms (SNPs) could be detected in exon 12 of the PDGFR-α gene (rs1873778), in three cases SNPs were found in exon 20 of the EGFR gene (rs1050171). No mutations were found in the KIT and KRAS gene., Conclusions: All tumors showed a COX-2 expression as well as an EGFR expression except for one case and a wild-type KRAS status. No activating mutations in the EGFR, KIT and PDGFR-α gene could be detected. Our data may indicate a potential for targeted therapies, but if these therapeutic strategies are of benefit in CASTLE remains to be determined., Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1658499296115016.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. They can occur anywhere in the gastrointestinal tract, and rarely outside the digestive tract. We herein report a case of primary gastrointestinal stromal tumor that was resected from the liver of a 56-year-old male, which is the sixth description of a primary hepatic gastrointestinal stromal tumor. The tumor was shown to be completely limited within the liver by radiological, intraoperative and pathological examinations. The pathological results demonstrated an intermediate risk gastrointestinal stromal tumor, and immunohistochemical expression of CD117 was positive. Although rare, we suggested that GISTs should be considered in the differential diagnosis of hepatic nodules, and that not all hepatic gastrointestinal stromal tumors should automatically be considered to be metastases from a primary gastrointestinal site.

Unlabelled: ABSTRACT Objective: The tyrosine kinase inhibitor nilotinib has potent inhibitory activity against the stem cell growth factor receptor c-Kit and platelet-derived growth factor receptor (PDGFR). The present study aimed to determine whether nilotinib suppresses airway remodeling and whether its effect is associated with the c-Kit and PDGFR pathways. We also aimed to compare the effect of nilotinib and imatinib on remodeling., Methods: We developed a mouse model of airway remodeling, which includes smooth muscle thickening, in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice a week for 3 months. Mice were treated with nilotinib or imatinib during the OVA challenge., Results: Compared with control mice, the mice chronically exposed to OVA developed sustained eosinophilic airway inflammation, airway hyperresponsiveness (AHR), and exhibited features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of nilotinib significantly inhibited eosinophilic inflammation, AHR, and remodeling in mice chronically exposed to OVA. Nilotinib showed a trend of more potent effect than imatinib on attenuating remodeling in hydroxyproline assay and smooth muscle staining. Nilotinib treatment significantly reduced the expression of phosphorylated (p)-c-Kit, p-PDGFRβ, and p-extracellular signal-regulated kinase 1/2. The expression levels of the genes encoding c-Kit and PDGFRβ were also reduced by nilotinib treatment. Treatment with nilotinib did not affect significantly the level of OVA-specific IgE and IgG1 in serum. In vitro, nilotinib significantly inhibited cell proliferation of fibroblast., Conclusions: These results suggest that nilotinib administration can prevent airway inflammation, AHR, and airway remodeling associated with chronic allergen challenge.

Different protocols exist for in vitro development of HuMCs from hematopoietic stem cells, which results in distinct mast cells regarding molecular markers and activation patterns. Here, we introduce a SR profile using immunological, neurogenic, and pharmacological stimuli to characterize cellular functionality. Mast cells were obtained from three culture protocols using two types of PBdMCs (CD34⁺ PBdMC or CD133⁺ PBdMC) and one type of CBdMC (CD133⁺ CBdMC). We analyzed resting cells for specific mast cell markers at protein and mRNA levels, thereby creating a molecular profile. To characterize the SR profile, we stimulated cells with anti-IgE, C3a, C5a, Substance P, or Compound 48/80 and measured the release of histamine and cytokines (IL-10, IL-13, GM-CSF, TNF-α). Molecular profiling revealed that CD133⁺ CBdMC expressed less chymase, FcεRIα, and CD203c but more CD117 compared with CD34⁺ and CD133⁺ PBdMC. The SR profile for histamine release illustrated a functional heterogeneity between PBdMC and CBdMC. PBdMC released >10% histamine upon stimulation with anti-IgE, C3a, Substance P, and Compound 48/80, whereas CBdMC only reacted to C3a. Cytokine secretion was only detected after anti-IgE stimulation. Here, the SR profile identified the CD133⁺ PBdMC as the most active cells regarding secretion of IL-10, IL-13, GM-CSF, and TNF-α. Cells from all three culture protocols, however, produced IL-10 spontaneously at comparable levels. We recommend validating mast cell cultures by means of molecular and SR profiles to characterize the mast cells and enhance consensus among studies., (© 2014 Society for Leukocyte Biology.)

The molecular phenotypic heterogeneity of mast cells (MCs) makes them attractive as potential therapeutic targets in anti-cancer adjuvant therapy. Mast cell aggregations observed in tumors suggested their involvement in tumor pathogenesis. Despite several studies using mast cell tryptase, MCs' involvement in the progression of prostate tumors has not been demonstrated. The aim of our study was to identify and quantify the phenotypic heterogeneity of MCs in prostate lesions. Our study included 7 cases of normal prostate, 25 cases of benign epithelial hyperplasia and 64 cases of prostate carcinoma. MCs were immunohistochemically assessed using three markers: tryptase, chymase and CD117. Two immunophenotypes of MCs were identified in benign lesions: tryptase+/CD117+/chymase- and tryptase-/chymase+/CD117+, located in peritumoral areas. Intratumoral MC phenotype of malignant lesions was characterized by tryptase+/chymase+/CD117+, while in the peritumoral areas three different MCs phenotypes were identified: tryptase+/chymase+/CD117-, tryptase+/CD117+/chymase- and chymase+/CD117+/tryptase-. Our results suggest the correlation of chymase positive MCs of the peritumoral areas and CD117 positive MCs of the intratumoral areas with tumor grade.

Counting mast cells in gastrointestinal (GI) mucosal biopsies is becoming an increasingly common practice. The primary reason for this exercise is to evaluate for possible involvement by systemic mastocytosis (SM). However, the features of mastocytosis in GI biopsies are not well described. In addition, recent studies have suggested that increased mast cells may be involved in the pathogenesis of some cases of diarrhea-predominant irritable bowel syndrome (IBS); the term "mastocytic enterocolitis" has been proposed for such cases. As the baseline mast cell density in colonic biopsies from normal patients has not been established in large cohorts, there is no widely accepted threshold for what constitutes increased mucosal mast cells. The aims of this study were (1) to determine the utility of GI biopsies for the diagnosis of SM, (2) to characterize the clinical, histologic, and immunohistochemical features of mastocytosis in the GI tract, (3) to determine mast cell density in normal colonic mucosa from a large cohort of asymptomatic patients, and (4) to compare these findings with those from patients with diarrhea-predominant IBS. Twenty-four patients with SM involving the GI tract, 100 asymptomatic patients, and 100 patients with IBS (the latter 2 groups with histologically normal colonic biopsies) were included. For the mastocytosis group, 107 biopsies (70 involved by mastocytosis; 67 mucosal, 3 liver) from 20 women and 4 men were evaluated (median age 59 y). The most commonly involved site was the colon (19 patients, 95%), followed by ileum (86%), duodenum (80%), and stomach (54%). In 16 cases (67%), the first diagnosis of SM was made on the basis of GI biopsies. Seventeen patients had documented cutaneous mastocytosis. Fifteen of 17 patients who underwent bone marrow biopsy had marrow involvement by SM. Eighteen patients had indolent disease, and 6 had aggressive disease (including all 3 with liver involvement). The most common GI symptom was diarrhea, followed by abdominal pain, nausea, weight loss, bloating, vomiting, or reflux. Liver disease presented with hepatomegaly and ascites. Endoscopic abnormalities (observed in 62%) included erythema, granularity, and nodules. Histologically, involved biopsies were characterized by infiltrates of ovoid to spindle-shaped mast cells in aggregates or sheets in the lamina propria, sometimes forming a confluent band underneath the surface epithelium; 25% of biopsies had only focal involvement (single aggregate). Prominent eosinophils were seen in 44% of involved colonic/ileal biopsies and 16% of duodenal biopsies. Mast cells were highlighted by diffuse membranous staining for KIT and CD25. In the nonmastocytosis groups, all biopsies contained singly dispersed mast cells with no aggregates. The mean highest mast cell counts (in a single high-power field) for asymptomatic patients and IBS patients were 26 (range, 11 to 55) and 30 (range, 13 to 59), respectively. In summary, GI (especially colonic) biopsies can establish a diagnosis of SM in patients with GI symptoms. GI involvement is usually subtle and is often associated with prominent eosinophils, which may obscure the mast cell infiltrate. KIT and CD25 are invaluable markers for the diagnosis. Mast cell density in colonic mucosa from asymptomatic patients is highly variable. Although patients with diarrhea-predominant IBS on average have mildly increased mast cells, the overlap in range with that of control patients is too great for this difference to be clinically useful. These findings argue against the utility of counting GI mucosal mast cell in patients with chronic diarrhea.