286 research outputs found
Analysis of DNA mismatch repair gene expression and mutations in thyroid tumours
Alterations of DNA mismatch repair genes, primarily demonstrated in hereditary nonpolyposis colorectal carcinomas, were reported to be of relevance for the progression of several sporadic tumours. In this study, the expression and mutations of MLH1, MSH2, PMS1 and PMS2 in a panel of thyroid tumours, including nodular hyperplasia, follicular adenomas and carcinomas, were investigated. The expressions of MLH1, MSH2 and PMS1 were generally higher in malignant tumours than in benign lesions (p<0.01). This observation can find potential diagnostic application in the differentiation of follicular adenomas from follicullar carcinomas of the thyroid. No point mutations in the DNA mismatch repair genes MSH2 (exon 12, 13) and MLH1 (exon 15, 16) were found
Cytokeratin positivity in paraffin-embedded malignant melanomas : comparative study of KL1, A4 and Lu5 antibodies
The unclear role of cytokeratin (CK) in the progression and diagnostics of malignant melanomas stimulated us to compare the reactivity of three antibodies directed to CK in 109 paraffin-embedded melanomas. By far the majority of melanomas did not express cytokeratin even at the<1% level, only vimentin. In about 6% of melanomas it was possible to find CK expression ranging between 3 and 40% of melanoma cells. There was a correlation between CK expression and pTstage. Cytokeratin-expressing tumours were found in the more advanced pT-stages. The independent prognostic values of none of the three CK antibodies investigated could be shown
Proposal of a new grading system for malignant fibrous histiocytomas
The proposed grading system for malignant fibrous histiocytomas (MFH) comprises 3 grades of malignancy. Analogous to other grading systems, the system includes the factors of mitotic rate and necrosis. In addition to these two factors, the concept of cellularity was included. The prognostic relevance of the grading systems published by Costa, Coindre, van Unnik, Pezzi and Tsujimoto as well as the grading system proposed by the present study was tested on 161 MFH. The results showed that all grading systems tested produced clearly significant differences (p<0.01) with regard to the survival estimated for patients with various grades of malignancy. These results revealed the superiority of systems that use 3 grades of malignancy over a 2-grade classification. The proposed grading system yielded a lower percentage of grade II tumours (37%) than the grading systems of Coindre (60%) and van Unnik (70%). In the multivariate analysis of all grading systems, the proposed grading system was the only one to show prognostic relevance (p<0.05)
Validation of tissue microarrays for immunohistochemical profiling of cancer specimens using the example of human fibroblastic tumors
Exonic deletions of mismatch repair genes MLH1 and MSH2 correlate with prognosis and protein expression levels in malignant melanomas
The mutations of MLH1 and MSH2 have been reported to be responsible for malignant transformation and tumour progression in several sporadic tumours. Eighty-six primary malignant melanomas with known follow-up were investigated. Point mutations of DNA mismatch repair MLH1 and MSH2 in malignant melanomas were not found. Exon 12 (MSH2) was not present in 26 out of the 86 melanomas and exon 13 (MSH2) was lost in 25 of the tumours. The loss of exon 15 (MLH1) was observed in 22 out of the 86 tumours and the loss of exon 16 (MLH1) in 24 melanomas. The loss of exons correlated strongly with the loss of MLH1 and MSH2 protein expression. In multivariate analysis, including all 4 exons and expressions of MLH1 and MSH2, prognostic significance was found only for loss of exon 12 (MSH2) and loss of exon 15 (MLH1)
Characterization of Desmoglein Expression in the Normal Prostatic Gland. Desmoglein 2 Is an Independent Prognostic Factor for Aggressive Prostate Cancer
Purpose:
The expression of desmogleins (DSGs), which are known to be crucial for establishing and maintaining the cell-cell adhesion required for tissue integrity, has been well characterized in the epidermis and hair follicle; however, their expression in other epithelial tissues such as prostate is poorly understood. Although downregulation of classical cadherins, such as E-cadherin, has been described in prostate cancer tissue samples, the expression of desmogleins has only been previously reported in prostate cancer cell lines. In this study we characterized desmoglein expression in normal prostate tissues, and further investigated whether Desmoglein 2 (DSG2) expression specifically can serve as a potential clinical prognostic factor for patients diagnosed with primary prostate cancer.
Experimental Design:
We utilized immunofluorescence to examine DSG2 expression in normal prostate (n = 50) and in a clinically well-characterized cohort of prostate cancer patients (n = 414). Correlation of DSG2 expression with clinico-pathological characteristics and biochemical recurrence was analyzed to assess its clinical significance.
Results:
These studies revealed that DSG2 and DSG4 were specifically expressed in prostatic luminal cells, whereas basal cells lack their expression. In contrast, DSG1 and DSG3 were not expressed in normal prostate epithelium. Further analyses of DSG2 expression in prostate cancer revealed that reduced levels of this biomarker were a significant independent marker of poor clinical outcome.
Conclusion:
Here we report for the first time that a low DSG2 expression phenotype is a useful prognostic biomarker of tumor aggressiveness and may serve as an aid in identifying patients with clinically significant prostate cancer
Role of Dok-1 and Dok-2 in Leukemia Suppression
Chronic myelogenous leukemia (CML) is characterized by the presence of the chimeric p210bcr/abl oncoprotein that shows elevated and constitutive protein tyrosine kinase activity relative to the normal c-abl tyrosine kinase. Although several p210bcr/abl substrates have been identified, their relevance in the pathogenesis of the disease is unclear. We have identified a family of proteins, Dok (downstream of tyrosine kinase), coexpressed in hematopoietic progenitor cells. Members of this family such as p62dok(Dok-1) and p56dok-2(Dok-2) associate with the p120 rasGTPase-activating protein (rasGAP) upon phosphorylation by p210bcr/abl as well as receptor and nonreceptor tyrosine kinases. Here, we report the generation and characterization of single and double Dok-1 or Dok-2 knockout (KO) mutants. Single KO mice displayed normal steady-state hematopoiesis. By contrast, concomitant Dok-1 and Dok-2 inactivation resulted in aberrant hemopoiesis and Ras/MAP kinase activation. Strikingly, all Dok-1/Dok-2 double KO mutants spontaneously developed transplantable CML-like myeloproliferative disease due to increased cellular proliferation and reduced apoptosis. Furthermore, Dok-1 or Dok-2 inactivation markedly accelerated leukemia and blastic crisis onset in Tec-p210bcr/abl transgenic mice known to develop, after long latency, a myeloproliferative disorder resembling human CML. These findings unravel the critical and unexpected role of Dok-1 and Dok-2 in tumor suppression and control of the hematopoietic compartment homeostasis
CaracterĂsticas anatĂ´micas da cateterização da uretra e bexiga de camundongos e ratos fĂŞmeas. Instrumento essencial na pesquisa prĂ© clĂnica
To present fundamental anatomical aspects and technical skills necessary to urethra and urinary bladder catheterization in female mice and rats. Urethral and bladder catheterization has been widely utilized for carcinogenesis and cancer research and still remains very useful in several applications: from toxicological purposes as well as inflammatory and infectious conditions to functional aspects as bladder dynamics and vesicoureteral reflux, among many others. Animal models are in the center of translational research and those involving rodents are the most important nowadays due to several advantages including human reproducibility, easy handling and low cost. Although technical and anatomical pearls for rodent urethral and bladder access are presented as tackles to the advancement of lower urinary tract preclinical investigation in a broaden sight, restriction to female animals hampers the male microenvironment, demanding future advances262Apresentar aspectos anatĂ´micos fundamentais e habilidades tĂ©cnicas necessárias para cateterismo da uretra e bexiga em ratos e camundongos fĂŞmeas. Cateterismo vesical tem sido amplamente utilizado na pesquisa do câncer e carcinogĂŞnese, alĂ©m de várias outras aplicações, desde fins toxicolĂłgicos, condições inflamatĂłrias e infecciosas atĂ© aspectos funcionais como a dinâmica vesical e refluxo vesico-ureteral, entre muitos outros. Os modelos animais estĂŁo no centro da investigação de translação e os roedores sĂŁo os mais importantes devido a várias vantagens, incluindo reprodutibilidade humana, o fácil manuseio e baixo custo. Apesar de permitir o desenvolvimento da investigação prĂ©-clĂnica do trato urinário inferior, o modelo se restringe aos animais do sexo feminino, de modo que avanços futuros sĂŁo necessário
- …