Biomedical subjects

Axel Walch

Publications and source records attributed to Axel Walch.

13 recordsLinked to original sources

PubMed2006

Aurora kinase A messenger RNA overexpression is correlated with tumor progression and shortened survival in head and neck squamous cell carcinoma.

PURPOSE: Aurora kinase A (AURKA/STK15/BTAK) encodes a serine/threonine kinase associated with chromosomal distribution and its up-regulation induces chromosomal instability, thereby leading to aneuploidy and cell transformation in several types of cancer. In this study, we investigated the role of AURKA in head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: The mRNA expression levels of AURKA were compared in tumor tissues of 66 HNSCC patients with those in corresponding normal squamous epithelium by real-time quantitative reverse transcriptase-PCR. In addition, the association between AURKA mRNA and protein expression, centrosome abnormalities, and aneuploidy was studied in a subset of cases (n=34). All molecular variables were correlated to histomorphologic findings and clinical follow-up data of the patients. RESULTS: AURKA mRNA up-regulation was significantly associated with tumor stage and the occurrence of regional lymph node, as well as distant metastasis (P<0.0001 for all). Similarly, a correlation was found for protein expression and the occurrence of regional lymph node (P=0.0183) and distant metastasis (P=0.03). The mRNA was positively associated with protein expression (P=0.003) and centrosome abnormalities (P=0.03). Cox regression analysis revealed that AURKA mRNA up-regulation correlated with disease-free survival of the patients (P=0.03) as well as shorter overall survival (P<0.001). CONCLUSIONS: We conclude that the up-regulation of AURKA mRNA may play a critical role in the tumor progression of HNSCC and provides useful information as a prognostic factor for HNSCC patients.

Aurora Kinase A↗

PubMed2006

Centrosome-, chromosomal-passenger- and cell-cycle-associated mRNAs are differentially regulated in the development of sporadic colorectal cancer.

Dysregulation of the centrosome complex and chromosomal segregation has been associated with aneuploid cells and aggressive solid tumours, but the relevance of this mechanism to the adenoma-carcinoma sequence of sporadic colorectal cancer (sCRC), especially tumours showing chromosomal instability (CIN), is still unknown. In a series of matching normal epithelial cells (n = 41), dysplastic cells (n = 18), and invasive carcinoma cells (n = 41) from cases with sCRC, mRNA levels of the centrosomal kinase Aurora-A/STK15 and the chromosomal passenger- and cell cycle-associated molecules Incenp, Survivin, Mad-2, and Cyclin-D1 were therefore measured with specific reference to the type of genetic instability. Compared with normal epithelium, significant up-regulation of mRNAs was already present for Aurora-A/STK15 (p = 0.0313) in dysplastic cells and for all investigated markers in invasive carcinoma. Whereas Aurora-A/STK15 mRNA levels were similarly up-regulated in dysplastic and invasive carcinoma cells (p = 0.0797), Survivin (p = 0.0046) and Cyclin-D1 (p = 0.0017) mRNA levels increased from dysplastic to invasive carcinoma cells. In carcinomas, Incenp mRNA correlated with T category (p = 0.0149), and Survivin (p = 0.0382) and Cyclin-D1 (p = 0.0185) were associated with tumour differentiation. Importantly, a significantly higher (p = 0.0419) fold-change of Aurora-A/STK15 mRNA (p = 0.0419), but not Incenp, Survivin, Mad-2 or Cyclin-D1, was observed in sCRC cases with CIN (n = 29) when compared with tumours showing microsatellite instability (MIN, n = 10). The present data are the first to show an early increase of the centrosomal kinase Aurora-A/STK15 in the adenoma-carcinoma sequence of sCRC. The regulation of this kinase differs in CIN- and MIN-type sCRCs and the pattern of changes is different from those of the cell-cycle-associated markers Survivin, Mad-2, and Cyclin-D1. This reinforces the concept of preferential dysregulation of the centrosome complex in CIN-type (aneuploid), compared with MIN-type, sporadic colorectal cancers and may influence the response to and efficiency of novel therapeutics targeting Aurora kinases.

Adenoma↗

PubMed2005

Numerical and structural centrosome aberrations are an early and stable event in the adenoma-carcinoma sequence of colorectal carcinomas.

AIMS: Numerical and structural centrosome changes have been described for and linked with genetic instability in solid tumors. Here, we specifically address centrosome aberrations in the adenoma-carcinoma sequence of colorectal cancer by detailed evaluation of gamma-tubulin staining patterns. METHODS: Formalin-fixed and paraffin-embedded specimens (normal colonic epithelium n=21; low-grade intraepithelial neoplasia n=27, high-grade intraepithelial neoplasia n=16 and invasive adenocarcinomas n=33) were stained by an anti-gamma-tubulin antibody using standard immunofluorescence. Three-dimensional image stacks of the stainings were recorded (Zeiss LSM510 confocal microscope), followed by numerical and structural data analysis (DIAS software package) and statistical evaluation (NCSS-software). RESULTS: The mean centrosome signal per cell differed significantly (P<0.0001) between normal colonic epithelium (0.8775) and each low-grade intraepithelial neoplasia (1.787), high-grade intraepithelial neoplasia (2.259) and invasive carcinomas (2.267). Similarly, both the centrosomes' structural entropy (SE) and minimal spanning tree (MST) differed significantly (P<0.001) between normal (SE=3.956, MST=38.78) and each low- (SE=6.39, MST=26) and high-grade intraepithelial neoplasia (SE=5.75, MST=26.97) and invasive carcinoma (SE=6.86, MST=28.08). CONCLUSION: Numerical and structural centrosome dysregulation is seen as early as in low-grade dysplastic lesions of the adenoma-carcinoma sequence of colorectal carcinomas and may, as such, play an initial role in the carcinogenic process.

Adenocarcinoma↗

PubMed2005

Human archival tissues provide a valuable source for the analysis of spatial genome organization.

Sections from archival formalin-fixed, paraffin wax-embedded human tissues are a valuable source for the study of the nuclear architecture of specific tissue types in terms of the three-dimensional spatial positioning and architecture of chromosome territories and sub-chromosomal domains. Chromosome painting, centromeric, and locus-specific probes were hybridized to tissue microarrays prepared from formalin-fixed paraffin wax-embedded samples of pancreas and breast. The cell nuclei were analyzed using quantitative three-dimensional image microscopy. The results obtained from non-neoplastic pancreatic cells of randomly selected individuals indicated that the radial arrangement of the chromosome 8 territories as well as their shape (roundness) did not significantly differ between the individuals and were in accordance with assumptions of a probabilistic model for computer simulations. There were considerable differences between pancreatic tumor and non-neoplastic cells. In non-neoplastic ductal epithelium of the breast there was a larger, but insignificant, variability in the three-dimensional positioning of the centromere 17 and HER2 domains between individuals. In neoplastic epithelial breast cells, however, the distances between centromere and gene domains were, on average, smaller than in non-neoplastic cells. In conclusion, our results demonstrate the feasibility of studying the genome architecture in archival, formalin-fixed, paraffin wax-embedded human tissues, opening new directions in tumor research and cell classification.

Breast↗

PubMed2005

Copy number gains on 22q13 in adenoid cystic carcinoma of the salivary gland revealed by comparative genomic hybridization and tissue microarray analysis.

Adenoid cystic carcinoma (ACC) of the salivary gland is a neoplasm characterized by slow but inevitable local progression and terminal hematogenous metastasis. To detect novel imbalanced chromosomal regions associated with tumorigenesis, we used chromosomal comparative genomic hybridization to screen 27 ACC. The most common aberration was copy number gain of 22q13 (nine cases) followed by gains of 16p (seven cases) and 17q (four cases) and copy number losses on 6q (six cases). To further delineate the prevalence of 22q13 copy number gains in ACC, fluorescence in situ hybridization was performed for five bacterial/phage artificial chromosome (BAC/PAC) probes from the 22q13 consensus region with 57 ACC on a tissue microarray. The overall prevalence of copy number gains on 22q13 was 30% of the tumors in the fluorescence in situ hybridization analysis, irrespective of histologic differentiation (cribriform/tubular vs. solid) or tumor event (primary vs. recurrent). We therefore assume that copy number gain of 22q13 is a novel frequent finding in ACC that may be involved in the initial pathogenesis of this neoplasm by proto-oncogene activation.

Adult↗

PubMed2005

Differential KIT expression in histological subtypes of adenoid cystic carcinoma (ACC) of the salivary gland.

Adenoid cystic carcinoma (ACC) of the salivary gland is characterized by a prolonged but inevitably unfavorable clinical course. Recent studies suggested the transmembrane tyrosine kinase KIT to be involved in ACC pathogenesis. To investigate KIT expression in histologically defined subgroups of ACC and to clarify whether KIT gene copy number gain contributes to KIT overexpression, tumor tissue microarray sections including 55 ACC tumors were analyzed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). The prevalence of positive KIT immunostaining was 89% (49/55). Strong immunostaining of KIT was only found in cribriform and tubular but never in solid subtypes (p=0.02). Average KIT staining intensity was higher in cribriform and tubular (n=37) compared to solid (n=18) ACC subtypes (p=0.005). FISH analysis revealed copy number gains of the KIT gene in 6.1% (3/49) of tumors analyzed. Our results implicate that specific KIT tyrosine kinase inhibitors such as imatinib, might be used in future therapeutic approaches against subgroups of ACC.

Carcinoma, Adenoid Cystic↗

PubMed2004

Coamplification and coexpression of GRB7 and ERBB2 is found in high grade intraepithelial neoplasia and in invasive Barrett's carcinoma.

The human growth factor receptor-bound protein 7 gene (GRB7), the founding member of a family of adaptor molecules has been shown to regulate cell migration and has been implicated in tumor progression. GRB7 is localized in close proximity to the ERBB2 gene within an amplicon previously identified in Barrett's adenocarcinoma (BCA). We evaluated gene amplification and mRNA expression of GRB7 and ERBB2 in Barrett's carcinoma and its associated precursor lesions to assess their possible role in Barrett's malignant transformation. Copy number and expression levels were analyzed by Q-PCR (GRB7, ERBB2) and QRT-PCR (GRB7, ERBB2) using TaqMan technology and fluorescence in situ hybridization (ERBB2) in a series of 24 laser-microdissected samples of Barrett's carcinomas and 32 samples of associated premalignant lesions. Parallel analysis of gene copy number changes and expression levels demonstrated that GRB7 and ERBB2 displayed concomitant elevated expression levels and increased copy numbers in 32% of Barrett's carcinomas. There was a correlation between GRB7 and ERBB2 in BCA at the DNA level (r(s) = 0.76, p < 0.001) and the mRNA level (r(s) = 0.89, p < 0.001). Moreover, coamplification (r(s) = 0.97, p < 0.001) and coexpression (r(s) = 0.81, p < 0.001) of GRB7 and ERBB2 are shown to be already present in a subset of BCA associated high-grade intraepithelial neoplasia (HGIN), possibly reflecting a role of a concerted expression of GRB7 and ERBB2. No alterations, neither gene amplification nor overexpression were detected in Barrett's carcinoma associated low grade intraepithelial neoplasia (LGIN), intestinal metaplasia (IM) and squamous epithelium, indicating that alterations of GRB7 and ERBB2 are late events in the carcinogenesis of Barrett's esophagus. These findings may be of particular interest because the transition from high grade intraepithelial neoplasia to invasive carcinoma is a crucial step in malignant transformation in Barrett's carcinogenesis and might underline the putative role of GRB7 and ERBB2 in cell migration and tumor invasion.

Adenocarcinoma↗

PubMed2004

Giant ancient schwannoma of pancreatic head treated by extended pancreatoduodenectomy.

We report a case of a 55-year-old woman who was transferred from another center to our university clinic after diagnostic laparotomy with a pancreatic head tumor which was seen to encase the portal vein. Although intraoperative biopsies were performed, a histologic diagnosis of the tumor was not possible before giving suspect to a malignant tumor being resectable only with a vascular resection. In a second operation we performed a pylorus-preserving pancreatoduodenectomy. Due to adhesion of the tumor to the portal vein, a segmental resection and end-to-end anastomosis of the portal vein was necessary. Postoperative histologic diagnosis revealed an ancient schwannoma which was removed in toto being a rare report of this benign tumor in the pancreatic head. Ten months after the operation the patient is without any health problems. Partial resection of the portal vein, which is considered to be a safe procedure in high volume centers, stands in contrary to surgical nihilism of pancreatic head tumors suspecting advanced tumors with vascular involvement.

Female↗

PubMed2004

Array-based comparative genomic hybridization for the detection of DNA sequence copy number changes in Barrett's adenocarcinoma.

Array-based comparative genomic hybridization (aCGH) allows the identification of DNA sequence copy number changes at high resolution by co-hybridizing differentially labelled test and control DNAs to a micro-array of genomic clones. The present study has analysed a series of 23 formalin-fixed, paraffin wax-embedded tissue samples of Barrett's adenocarcinoma (BCA, n = 18) and non-neoplastic squamous oesophageal (n = 2) and gastric cardia mucosa (n = 3) by aCGH. The micro-arrays used contained 287 genomic targets covering oncogenes, tumour suppressor genes, and DNA sequences localized within chromosomal regions previously reported to be altered in BCA. DNA sequence copy number changes for a panel of approximately 50 genes were identified, most of which have not been previously described in BCA. DNA sequence copy number gains (mean 41 +/- 25/BCA) were more frequent than DNA sequence copy number losses (mean 20 +/- 15/BCA). The highest frequencies for DNA sequence copy number gains were detected for SNRPN (61%); GNLY (44%); NME1 (44%); DDX15, ABCB1 (MDR), ATM, LAMA3, MYBL2, ZNF217, and TNFRSF6B (39% each); and MSH2, TERC, SERPINE1, AFM137XA11, IGF1R, and PTPN1 (33% each). DNA sequence copy number losses were identified for PDGFB (44%); D17S125 (39%); AKT3 (28%); and RASSFI, FHIT, CDKN2A (p16), and SAS (CDK4) (28% each). In all non-neoplastic tissue samples of squamous oesophageal and gastric cardia mucosa, the measured mean ratios were 1.00 (squamous oesophageal mucosa) or 1.01 (gastric mucosa), indicating that no DNA sequence copy number chances were present. For validation, the DNA sequence copy number changes of selected clones (SNRPN, CMYC, HER2, ZNF217) detected by aCGH were confirmed by fluorescence in situ hybridization (FISH). These data show the sensitivity of aCGH for the identification of DNA sequence copy number changes at high resolution in BCA. The newly identified genes may include so far unknown biomarkers in BCA and are therefore a starting point for further studies elucidating their possible role in Barrett's carcinogenesis.

Adenocarcinoma↗

PubMed2003

Distinct chromosomal imbalances in nonpolypoid and polypoid colorectal adenomas indicate different genetic pathways in the development of colorectal neoplasms.

Cytogenetic changes are widely unknown for nonpolypoid (synonymously termed as "flat" or "depressed") colorectal adenomas. A comparison with polypoid adenomas will contribute to the discussion whether different genetic pathways for colorectal tumorigenesis depending on its origin from nonpolypoid or polypoid adenomas exist. Tissue samples of nonpolypoid (n = 22), polypoid (n = 28) adenomas, carcinomas ex-nonpolypoid adenomas (n = 9), carcinomas ex-polypoid adenomas (n = 14), and normal colonic mucosa (n = 9) were investigated by comparative genomic hybridization of whole genomic DNA. Chromosomal imbalances were detected from average comparative genomic hybridization profiles for each entity. Nonpolypoid adenomas show recurrent chromosomal losses on chromosomes 16, 17p, 18, 20, and 22 and gains on chromosomes 2q, 4q, 5, 6, 8q, 12q, and 13q. In polypoid adenomas losses of whole chromosomes 16, 18, and 22 and gains of chromosomes 7q and 13 were detected. The frequency of copy number changes was higher in nonpolypoid compared to polypoid adenomas and early onset of chromosomal changes became apparent in low-grade dysplasias of nonpolypoid adenomas. Gains on chromosomes 2q, 5, 6, 8q, and 12q and losses on chromosomes 17p and 20 occurred exclusively in nonpolypoid adenomas, whereas 16p deletions are significantly more frequent in nonpolypoid than in polypoid adenomas. Carcinomas ex-nonpolypoid adenomas are characterized by more complex aberration patterns compared to nonpolypoid adenomas exhibiting frequent losses on chromosomes 8p, 12q, 14, 15q, 16, 17p, 18, and 22 and gains on 3q, 5, 6, 7, 8q, 12q, and 13, respectively. Normal colonic mucosa showed no chromosomal imbalances. Distinct differences of chromosomal imbalances between nonpolypoid and polypoid colorectal adenomas have been characterized that support the hypothesis that different genetic pathways may exist in the development of colorectal adenomas exhibiting nonpolypoid and polypoid phenotype.

Adenoma↗

PubMed2002

Recessive transmission of a multiple endocrine neoplasia syndrome in the rat.

We describe a novel hereditary cancer syndrome in the rat that is transmitted by a recessive gene mutation. Animals exhibiting the mutant phenotype develop multiple neuroendocrine malignancies within the first year of life. The endocrine neoplasia is characterized by bilateral adrenal pheochromocytoma, multiple extra-adrenal pheochromocytoma, bilateral medullary thyroid cell neoplasia, bilateral parathyroid hyperplasia, and pituitary adenoma. The appearance of neoplastic disease is preceded by the development of bilateral juvenile cataracts. Although the spectrum of affected tissues is reminiscent of human forms of multiple endocrine neoplasia (MEN), no germ-line mutations were detected in the Ret or Menin genes that are responsible for the dominantly inherited MEN syndromes in humans. Segregation studies in F1 and F2 crosses yielded frequencies of affected animals entirely consistent with a recessive autosomal mode of inheritance. The lack of the phenotype in F1 animals effectively excludes a germ-line tumor suppressor gene mutation as the causal event. The absence of mutation of known MEN genes and the unique constellation of affected tissues, plus the recessive mode of inheritance, lead us to conclude that the mutation of an as yet unknown gene is responsible for this syndrome of inherited neuroendocrine cancer.

Animals↗

PubMed2002

Analysis of the PTCH coding region in human rhabdomyosarcoma.

Inherited mutations of the human tumor suppressor gene Patched (PTCH) lead to an autosomal dominant disorder known as Nevoid Basal Cell Carcinoma Syndrome (NBCCS). The syndrome is characterized by a combination of developmental abnormalities and a predisposition to tumor formation. Tumors in patients with NBCCS include basal cell carcinoma, medulloblastoma, fibroma and rhabdomyosarcoma (RMS). RMS are also present in 15 % of mice haplodeficient for Ptch. To investigate whether mutations in PTCH are a general feature in rhabdomyosarcomagenesis we sequenced the protein-coding region in sporadic human cases of these tumors. For this purpose we first determined the distribution and frequency of polymorphisms in 23 exons of PTCH in 48 healthy caucasians. Ten new polymorphisms were identified (IVS11 + 15-17del AAA; IVS14 + 25T>C; 2485G>A; IVS15 + 9G>C; IVS17 + 21A>G; 3033T>C; 3149T>C; 3387T>C; 3617G>A; 4080C>T). Next, the PTCH coding region in 14 RMS was sequenced. Whereas one case with LOH at the PTCH locus was detected, none of the cases showed nonsense or missense mutations in the coding region of PTCH. These data do not support the existence of frequent mutations in the protein-coding region of PTCH in RMS.

DNA Mutational Analysis↗

PubMed2002

Chromosomal imbalances are associated with metastasis-free survival in breast cancer patients.

Multiple chromosomal imbalances have been identified in breast cancer using comparative genomic hybridization (CGH). Their association with the primary tumors' potential for building distant metastases is unknown. In this study we have investigated 39 invasive breast carcinomas with a mean follow-up period of 99 months (max. 193 months) by CGH to determine the prognostic value of chromosomal gains and losses. The mean number of chromosomal imbalances per tumor was 6.5+/-0.7 (range 2 to 18). The most frequent alterations identified in more than 1/3 of cases were gains on chromosomes 11q13, 12q24, 16, 17, and 20q, and losses on 2q and 13q. A significantly different frequency of chromosomal aberrations (p<or=0.05) was found between DNA-diploid and non-diploid tumors (gain on chromosome 17). Differences were also noted between tumors progressing to distant metastases within the period of follow-up and those which do not (gains on 11q13 and 12q24; loss on 12q). Significant univariate correlations (p<or=0.05) with the metastasis-free survival of patients were found for lymph node status, the cytometrical determined DNA ploidy (diploid/non-diploid) and anisokaryosis, and for DNA gains on 11q13, 12q24, 17, and 18p. An unexpected inverse correlation was found between clinical outcome and gains on 11q13 and 12q24. In multivariate analysis independent prognostic value, in addition to lymph node status, was found for chromosomal gains on 11q13, 12q24, 17 and 18p. Amplification on 20q, which did not correlate with metastasis-free survival in a univariate analysis, showed weak prognostic significance in combination with the nodal status. The prognostic value of chromosomal alterations - some of them by inverse correlation - suggests an interaction and/or compensation of the involved amplified genes and their effects on the occurrence of distant metastases in breast cancer patients.

Breast Neoplasms↗