Members of the Fos family of AP-1 transcription factors (c-Fos, FosB, FosB2, Fra-1 and Fra-2) are able to form dimers with Jun proteins which bind to the regulatory sequences of target genes. As many proteases involved in tumor invasion are AP-1-regulated, we assumed that Fos family members might be important for invasion of mammary carcinomas. Therefore, we performed transient transfections with expression vectors for c-Fos, FosB, FosB2, Fra-1 and Fra-2, followed by matrigel invasion assays. Fra-1 transfection resulted in a 2-4-fold increase of invasive cells in both cell lines. In a less degree, the invasive potential of MDA-MB231 cells was stimulated by Fra-2, whereas MCF7 invasion was enhanced by c-Fos and FosB. By double-labelling immunocytochemistry, PAI-1 up-regulation was observed in cells transfected with c-Fos, Fra-1 and Fra-2 expression vectors, whereas MMP1 and MMP9 expression was not affected. Results of cotransfection with a MMP9 promoter construct and AP-1 expression vectors do not indicate a direct up-regulation of MMP9 expression by Fos proteins except a positive effect of c-Fos in MCF7 cells. In parallel, expression of Fos family members as determined by Western Blot analysis in 75 mammary carcinomas was correlated with MMP1, MMP9, PAI-1 and uPAR protein levels in the tumors. Interestingly, high FosB levels were significantly associated with MMP1 overexpression, whereas expression of c-Fos and phosphorylated Fra-1 correlated with MMP9 protein levels. Strong Fra-2 expression correlated with high levels of MMP9, PAI-1, the uPA/PAI-1 complex and early recurrence. These data indicate that Fos proteins, especially Fra-1, c-Fos and Fra-2, might be involved in invasion of breast cancer cells.

Extracellular-regulated kinases (ERK1, ERK2) play important roles in the malignant behaviour of breast cancer cells in vitro. In our present study, 148 clinical breast cancer samples (120 cases with follow-up data) were studied for the expression of ERK1, ERK2 and their phosphorylated forms p-ERK1 and p-ERK2 by immunoblotting, and p-ERK1/2 expression in corresponding paraffin sections was analysed by immunohistochemistry. The results were correlated with established clinical and histological prognostic parameters, follow-up data and expression of seven cell-cycle regulatory proteins as well as MMP1, MMP9, PAI-1 and AP-1 transcription factors, which had been analysed before. High p-ERK1 expression as determined by immunoblots correlated significantly with a low frequency of recurrences and infrequent fatal outcome (P ¼ 0.007 and 0.008) and was an independent indicator of long relapse-free and overall survival in multivariate analysis. By immunohistochemistry, strong p-ERK staining in tumour cells was associated with early stages (P ¼ 0.020), negative nodal status (P ¼ 0.003) and long recurrence-free survival (P ¼ 0.017). In contrast, expression of the unphosphorylated kinases ERK1 and ERK2 was not associated with clinical and histological prognostic parameters, except a positive correlation with oestrogen receptor status. Comparison with the expression of formerly analysed cell-cycle-and invasion-associated proteins corroborates our conclusion that activation of ERK1 and ERK2 is not associated with enhanced proliferation and invasion of mammary carcinomas. Growth factors or cytokines exert positive and negative effects on cell proliferation and differentiation. After binding to their membrane receptors, the message is relayed to the nucleus by a complex system of intracellular signalling pathways. The majority of signalling molecules involved in these pathways are kinases, which are themselves activated by phosphorylation and repressed by their specific phosphatases. The mitogen-activated protein kinase (MAPK) signalling pathway includes a cascade of four groups of kinases (MAPKKKKs, MAPKKKs, MAPKKs and MAPKs). The MAPK kinase kinase kinases of the first level are phosphorylated in response to various extracellular stimuli through interaction with small GTP-binding proteins like Ras, Raf, etc. The activated enzymes then phosphorylate one of 14 kinases of the second level (the MAPKKKs, that is, Raf proteins, MEKK1-4, etc.), which themselves activate one of the MAPK kinases (MEK1 and 2, MKK3 -7) of the third level. Finally, these kinases (MAPKKs) activate MAP kinases, which are then able to phosphorylate transcription factors, which regulate the expression of genes involved in cell proliferation or differentiation. Three different, partly interacting signalling pathways have been identified in mammalian cells, leading to the activation of three types of MAP kinases: the MAP kinase JNK (Jun kinase) phosphorylates c-Jun, JunB, ATF2 and ELK1, etc., P38 activates ATF2, ELK-1 and MAX, whereas ERK1 and ERK2 phosphorylate...

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Background: The aim of this study was to evaluate the current management of skin-sparing mastectomy in German hospitals and to determine its oncologic safety. For this purpose, 100 surgeons were surveyed regarding their use of skin-sparing mastectomy. Results: Almost all surveyed hospitals performed skin-sparing mastectomy. Most of them believe that the recurrence rate is equal to that of conventional mastectomy. 95% regard inflammatory cancer as a contraindication to skin-sparing surgery. Most of the hospitals thin out the skin without leaving any macroscopic glandular tissue behind, and 73% leave the nipple-areola complex (NAC) on the basis of frozen sections. Volume replacement is most commonly done with latissimus dorsi muscle flaps and pedicled TRAM flaps. In 76% of the surveyed hospitals, reconstruction after mastectomy is performed by the gynecological department. Conclusion: Skin-sparing mastectomy is considered to be the best cosmetic option for breast reconstruction in selected breast cancer patients. At present, statistical proof of its oncologic safety is lacking. The surgical techniques used for skin-sparing mastectomy have not yet been standardized. In order to achieve standardization, careful discussion-making and evaluation remain important.