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Melanocytes show antigen expressions characteristic for the immune response effector cells, and the immune reactions in the skin, especially those with inflammation background, significantly affect the function of melanocytes. Among the cytokines produced by keratinocytes, the stem cell factor (SCF) plays a leading role in stimulating melanogenesis.To compare the expression level of stem cell factor (mSCF, pSCF) and the c-Kit receptor in the centre of the vitiligo patch and in the area of healthy skin adjacent to the vitiligo patch.The research material consisted of skin samples from a vitiligo lesion and from non-lesional skin adjacent to the vitiligo patch. Real Time PCR analysis (Applied Biosystems 7900HT) was performed to determine the expression level of the studied genes.The studies showed a statistically significant increase in the amount of mSCF within the vitiligo patch compared to both healthy skin of patients with vitiligo and controls. In patients with vitiligo, c-Kit receptor expression was significantly decreased in the area of the lesional skin compared to the healthy skin of the same patient and the skin of the control group.The membrane-bound form of the SCF is overexpressed within the vitiligo skin, which may indicate the participation of mSCF in the stimulation of melanogenesis in response to melanocyte damage. Decreased expression of C-Kit receptor by melanocytes in the vitiligo patch disrupts the ligand-receptor interaction and may therefore be related to melanocytes dysfunction and/or loss.

C-Kit protein is a transmembrane tyrosine kinase (TK) receptor (c-KitR-TK), which is predominantly expressed on mast cells (MCs) playing a role in tumor angiogenesis. It could be also expressed on epithelial breast cancer cells (EBCCs), but no data have been published regarding the correlation between mast cells positive to c-KitR (MCs-c-KitR), EBCCs positive to c-KitR (EBCCs-c-KitR), BC angiogenesis in terms of microvessel density (MVD) and the main clinic-pathological features. This study aims to evaluate the above parameters and their correlations in a series of selected 121 female early BC patients. It has been found a strong correlation between MVD and MCDPT, and MCs-c-KitR, MVD and MCs density positive to tryptase (MCDPT), and MCs-c-KitR and MCDPT by Pearson correlation. These data suggest an involvement of both MCDPT and MCs-c-KitR in BC tumor angiogenesis. Furthermore, BC tissue expressing c-KitR could be a putative predictive factor to c-KitR-TK inhibitors. In this way, selected patients with higher MCs-c-KitR could be candidate to receive c-KitR-TK inhibitors (e.g. masitinib, sunitinib) or tryptase inhibitors (e.g. nafamostat mesilate, gabexate mesilate).

Miconeedling has been used to augment the transdermal drug delivery. Combination modalities may accelerate and improve the repigmentation in vitiligo.To determine the efficacy and tolerability of combined microneedling with tacrolimus vs tacrolimus 0.1% ointment for the treatment of vitiligo.Forty-eight patients with vitiligo were randomized into two groups: group I applied tacrolimus once daily for 6 months. Group II received microneedling with topical tacrolimus at 2 weeks intervals for a maximum of 6 months. The assessment was based on the clinical improvement and immunohistochemical changes. Skin biopsies were taken at baseline and after the treatment for c-kit + expression.After treatment, the repigmentation75% was observed in 50% of the patients in group II compared to 29.2% in group I (The results suggest the superiority of the combination regimen (tacrolimus and microneedling) for vitiligo treatment.

Background Familial progressive hyperpigmentation (FPH) is an autosomal dominant disorder characterized by the appearance of hyperpigmented patches on the skin from early infancy that increase in size and number with age. Methods We report the clinical and molecular studies of an 11-year-old boy who had areas of hyperpigmentation since birth that had spread across his body as irregular hyperpigmented macules and papules, and include relevant history in family members. Results Affected members of his family shared a mutation in the c-KIT gene. All had progressive hyperpigmentation, in some cases accompanied by gastrointestinal stromal tumors and mastocytoma. There have been few reports of familial progressive hyperpigmentation together with systemic manifestations. Conclusions Molecular analysis of c-KIT should be considered in the presence of FPH with systemic involvement.

Gastrointestinalni stromalni tumor je nejcastějsim neepitelialnim tumorem zaživaciho traktu. V poslednich letech prodělaly velice rychlý vývoj možnosti jeho systemove lecby. Efektivita biologických připravků v paliativni indikaci byla důvodem k jejich zavedeni i v adjuvantnim podani. Zakladni pozici v prve paliativni linii i v adjuvantni indikaci u vysoce rizikových resekovaných GIST ma imatinib. Po jeho selhani v inicialni davce se doporucuje jeho eskalace a teprve pote lecba dalsimi biologickými preparaty jako sunitinib nebo regorafenib. Existuje cela řada preparatů, ktere byly ci jsou aktualně zkoumany v klinických studiich.

Background The survival and growth of melanocytes are controlled by the binding of stem cell factor to its cell surface receptor c-kit+ (CD117). We have observed that c-kit+ melanocytes existed in some lesions of vitiligo, while Melan A+ cells were absent. Objective To verify possible relation between c-kit+ expression and treatment response in non-segmental vitiligo lesions Methods Skin biopsies were done from the center of the 47 lesions from the 47 patients with non-segmental vitiligo. Expression of c-kit+ and Melan A, and amounts of melanin in the epidermis were assessed in each lesion, and treatment responses to excimer laser were evaluated. Results Thirty-five of the 47 lesions (74.5%) had c-kit+ phenotypes. There was significant difference of c-kit staining value between good responders in 3 months of excimer laser treatment (average of 24 sessions) and the others. Conclusion c-Kit expression in vitiliginous epidermis may be related to better treatment responses to excimer laser.

To investigate the c-kit expression in biliary tract cancer cell lines and histological sections from patients with extrahepatic cholangiocarcinoma (CC) and to evaluate the efficacy of in vitro and in vitro treatment with imatinib mesilate.The protein expression of c-kit in the human biliary tract cancer cell lines Mz-ChA-2 and EGI-1 and histological sections from 19 patients with extrahepatic CC was assessed by immunoblotting, immunocytochemistry, and immunohistochemistry. The anti-proliferative effect of imatinib mesilate on biliary tract cancer cell lines Mz-ChA-2 and EGI-1 was studied in vitro by automated cell counting. In addition, immunodeficient NMRI mice (Taconic) were subcutaneously injected with 5x10(6) cells of cell lines MzChA-2 and EGI-1. After having reached a tumour volume of 200 mm3, daily treatment was started intraperitoneally with imatinib mesilate at a dose of 50 mg/kg or normal saline (NS). Tumor volume was calculated with a Vernier caliper. After 14 d, mice were sacrificed with tumors excised and tumor mass determined.Immunoblotting revealed presence of c-kit in Mz-ChA-2 and absence in EGI-1 cells. Immunocytochemistry with c-kit antibodies displayed a cytoplasmatic and membraneous localization of receptor protein in Mz-ChA-2 cells and absence of c-kit in EGI-1 cells. c-kit was expressed in 7 of 19 (37%) extrahepatic human CC tissue samples, 2 showed a moderate and 5 a rather weak immunostaining. Imatinib mesilate at a low concentration of 5 micromol/L caused a significant growth inhibition in the c-kit positive cell line Mz-ChA-2 (31%), but not in the c-kit negative cell line EGI-1 (0%) (P0.05). Imatinib mesilate at an intermediate concentration of 10 micromol/L inhibited cellular growth of both cell lines (51% vs 57%). Imatinib mesilate at a higher concentration of 20 micromol/L seemed to have a general toxic effect on both cell lines. The IC50 values were 9.7 micromol/L and 11 micromol/L, respectively. After 14 d of in vitro treatment with imatinib mesilate, using the chimeric mouse model, c-kit positive Mz-ChA-2 tumors had a significantly reduced volume and mass as compared to NS treatment (P0.05). In contrast to that, treatment of mice bearing c-kit negative EGI-1 tumors did not result in any change of tumor volume and mass as compared to NS treatment.c-kit expression is detectable at a moderate to low protein level in biliary tract cancer. Imatinib mesilate exerts marked effects on tumor growth in vitro and in vitro dependent on the level of c-kit expression.

c-Kit Receptor is Essential for Functional Cardiac Repair Post-Myocardial Infarction Bilal Ayach, Makoto Yoshimitsu, Christopher Siatskas, Paul Lee, Hilda Lim, Fayez Dawood, Manyin Chen, Jeffrey A. Medin, Peter P. Liu; Medicine, The Heart and Stroke/Richard Lewar Centre of Excellence, Toronto, ON, Canada; Ontario Cancer Institute of the University Health Network, Toronto, ON, Canada; The University of Toronto, Toronto, ON, Canada

e16502 Background: In the last years published studies demonstrated that mast cells (MCs) contain pro-angiogenic factors associated with tumoral angiogenesis. Tryptase is the most abundant and potent pro-angiogenic substance contained in MCs secretory granules and it can be released in tumour microenvironment. Up to now few data have been published on the role of MCs in angiogenesis in both pancreatic ductal adenocarcinoma cancer tissue (PDACT) and adjacent normal tissue (ANT). Methods: In this study MCs density positive to C-Kit receptor (MCDP-C-KitR), MCs density positive to tryptase (MCDPT), MCs area positive to tryptase (MCAPT), angiogenesis in terms of microvascular density (MVD) and endothelial area (EA) were evaluated by immunohistochemistry and image analysis in both PDACT and ANT. All tissue samples were obtained from 45 patients with stage T2-3N0-1M0 (by AJCC for Pancreas Cancer Staging 7th Edition) who had undergone surgery. For each analyzed tissue parameter mean ± standard deviation was evaluated in both PDACT and ANT and differences were evaluated by Student t-test. Each analysed tissue parameter was then correlated each other by Pearson t-test analysis. Results: The mean value ± standard deviation (SD) regarding MCDP-C-KitR, MCDPT, MCAPT, MVD and EA in TT was 14.69±4.57, 13.31± 4,23, 171.41±62,39 µ2, 29.11±7.93, 201.82±70.05 µ2 respectively and the mean value ± SD in ANT was 5.61 ± 2.39, 5.13 ± 2.03, 54.43 ± 16.73 µ2, 11.45 ± 4.96, 67.60 ± 21.96 µ2, respectively. Differences in terms of mean value ± SD between PDACT and ANT were significant for each analyzed tissue biomarker (p ranged from 0,001 to 0,004 by t-test analysis; Table). Data demonstrated that MCDP-C-KitR MCDPT, MCAPT, MVD and EA significantly increased from ANT to PCT. In PCT it was showed a correlation between MCDP-C-KitR and MCDPT (r = 0.87, p = 0.01), MCDP-C-KitR and MVD (r = 0.74, p = 0.02), MCDP-C-KitR and MCAPT (r = 0.81, p = 0.01), MCDPT and MVD (r = 0.72, p = 0.02), MCD-C-KitR and EA (r = 0.73, p = 0.02), MCDPT and MCAPT (r = 0.85, p = 0.01), MCAPT and MVD (r = 0.76, p = 0.02), MCAPT and EA (r = 0.66, p = 0.03), MCDPT and EA (r = 0.69, p = 0.03), MVD and EA (r = 0.82, p = 0.01). Conclusions: Our data suggest that assessed tissue parameters increased from ANT to PDACT and that MCs are associated with angiogenesis in PDACT. On this basis inhibition of MCs by tyrosine kinase inhibitors such as masitinib or inhibition of tryptase by gabexate mesylate may be a novel antiangiogenetic approach in pancreatic cancer therapy.