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)

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)

Alterations of the retinoblastoma and p16 pathway correlate with promoter methylation in malignant fibrous histiocytomas

Recent reports indicate that the alterations in the p16 and pRb pathways can influence tumour progression and poor prognosis in several tumours. The objective of this study was to analyse p16 and pRb expression in161 patients with malignant fibrous histiocytomas (MFH). By immunohistochemistry, p16 and pRb were demonstrated in 25% and 56% of MFH, respectively. Cox regression analysis demonstrated an independent prognostic influence of both genes. Generally, the loss of p16 and pRb expression correlated with poorer prognosis. Promoter methylation of p16 was found in 16/42 of p16 negative MFH and of pRb in 2/42 of pRb-negative MFH. It can be concluded that p16 and pRb alterations play an important role in the progression of soft tissue sarcomas

Charakter - Lernen - Unterricht. Über Arbeitstugenden und Exzellenz als Ziele eines adaptiven Unterrichts

Erfolgreiches Lernen und Schulerfolg hängen nicht allein vom Erwerb akademischer Fähigkeiten ab. Ebenso relevant sind nonkognitive Faktoren, wie z. B. Selbstbilder, Selbstkontrolle, Lern- und Arbeitshaltungen. Solche Eigenschaften fehlen oftmals Kindern mit Lernproblemen, nicht zuletzt auch denen, die unter schwierigen sozialen Lebensverhältnissen aufwachsen. Diesen Kindern hilft es, wenn sie in ihrer Persönlichkeit gestärkt werden und auf eigene personale Ressourcen zurückgreifen können. In dem Beitrag soll ein Forschungsüberblick zu ausgewählten nonkognitiven Faktoren des Lernens gegeben werden und vor diesem Hintergrund didaktische und methodische Folgerungen für einen adaptiven Unterricht aufgezeigt werden