Andrea Tannapfel

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BACKGROUND Inactivation of the tumour suppressor gene p16 (CDKN2/MTS-1/INK4A) and K-ras mutations are among the most frequent genetic alterations in human malignancies. AIMS To investigate the tumour suppressor gene p16 and its possible association with K-ras mutations in intrahepatic cholangiocarcinomas of the liver. METHODS The status of p16 was(More)
The molecular causes for resistance of melanoma to apoptosis are currently only partly understood. In the present study, we examined gene transfer and expression of the proapoptotic BH3-only protein Noxa as an alternative approach to chemotherapy and investigated the molecular mechanisms regulating Noxa-induced apoptosis. Noxa gene transfer caused(More)
BACKGROUND The Raf/MEK/ERK (mitogen activated protein kinase-MAPK) signal transduction cascade is an important mediator of a number of cellular fates, including growth, proliferation, and survival. The BRAF gene, one of the human isoforms of RAF, is activated by oncogenic Ras, leading to cooperative effects in cells responding to growth factor signals. (More)
The microRNA encoding genes miR-34a and miR-34b/c represent direct p53 target genes and possess tumor suppressive properties as they mediate apoptosis, cell cycle arrest, and senescence. We previously reported that the miR-34a gene is subject to epigenetic inactivation by CpG methylation of its promoter region in primary prostate cancer and melanomas, and(More)
Cancer cells display widespread changes in DNA methylation that may lead to genetic instability by global hypomethylation and aberrant silencing of tumor suppressor genes by focal hypermethylation. In turn, altered DNA methylation patterns have been used to identify putative tumor suppressor genes. In a methylation screening approach, we identified ECRG4 as(More)
BACKGROUND MicroRNAs (miRNAs) are RNA molecules that are involved in the regulation of many cellular processes, including those related to human cancers. The aim of this study was to determine, as a proof of principle, whether specific candidate miRNAs could be detected in fine-needle aspirate (FNA) biopsies of pancreatic ductal adenocarcinoma (PDAC) and(More)
BACKGROUND The protein p73, the first identified homologue of the tumor suppressor gene p53 (also known as TP53), has been shown to induce apoptosis (programmed cell death), but its function in tumor development has not been established. This study was undertaken to investigate the expression of p73 in liver tissue of patients with hepatocellular carcinoma(More)
Aberrant Wnt-signaling caused by mutants of β-catenin, a key regulator of the canonical Wnt-signaling pathway, is frequently detected in cancer. Only recently, it was suggested that in hepatocellular carcinoma (HCC) the expression of the target gene glutamine synthetase (GS) is a highly reliable marker for the identification of β-catenin mutations. In order(More)
The tumor-suppressor genes p14(ARF), p16(INK4a) and Tp53 are commonly inactivated in many tumors. We investigated their role in the pathogenesis of 9 bile tract cancer cell lines and 21 primary sporadic extrahepatic bile duct carcinomas. p53 and p16 protein expression was examined by Western blot analysis and immunohistochemistry. Mutation screening of p53(More)
The suppressors of cytokine signaling (SOCS) are inhibitors of cytokine signaling that function via the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway. Recently, methylation of SOCS-1 and SOCS-3 has been implicated in the tumorigenesis of liver and lung cancer. This study was performed to elucidate the role of SOCS-1(More)