Peter Ulz

Publications

• 4.72

  Impact points

  High-resolution analysis of alterations in medullary thyroid carcinoma genomes.

  Karin Flicker, Peter Ulz, Harald Höger, Petra Zeitlhofer, Oskar A Haas, Annemarie Behmel, Wolfgang Buchinger, Christian Scheuba, Bruno Niederle, Roswitha Pfragner, Michael R Speicher

  International journal of cancer. Journal international du cancer. 10/2011;

  Hereditary and sporadic medullary thyroid carcinoma (MTC) are closely associated with RET proto-oncogene mutations. However, the role of additional changes in the tumor genomes remains unclear. Our objective was the identification of chromosomal regions involved in MTC tumorigenesis and to assess th... [more] Hereditary and sporadic medullary thyroid carcinoma (MTC) are closely associated with RET proto-oncogene mutations. However, the role of additional changes in the tumor genomes remains unclear. Our objective was the identification of chromosomal regions involved in MTC tumorigenesis and to assess their significance by using MTC-derived cell lines. We used array-CGH (comparative genomic hybridization) to map chromosomal imbalances in 52 primary tumors and ten metastases. Eleven tumors (11/52, 21%) were hereditary and 41 (41/52, 79%) were sporadic. Among the latter, 15 tumors (15/41, 37%) harbored RET mutations. Furthermore, we characterized five MTC cell lines in detail and evaluated the tumorigenicity by severe combined immunodeficiency (SCID)-mouse experiments. Most MTCs had only few copy number changes, and losses of chromosomes 1p, 4q, 19p and 22q were observed most frequently. The number of chromosomal aberrations increased in metastases. Twenty-three percent (12/52) of the primary tumors did not even show any chromosomal gains and losses. We injected three cell lines (two of these were without chromosomal changes and pathogenic RET mutations) into immune deficient SCID mice, and in each case, we observed rapid tumor growth at the injection sites. Our data suggest that MTCs-in contrast to most other tumor entities-do not acquire a multitude of genomic imbalances. SCID mouse experiments performed with chromosomally normal cell lines and without RET mutations suggest that presently unknown submicroscopic genomic changes are sufficient in MTC tumorigenesis.
• 34.28

  Impact points

  Germline mutations in BAP1 predispose to melanocytic tumors.

  Thomas Wiesner, Anna C Obenauf, Rajmohan Murali, Isabella Fried, Klaus G Griewank, Peter Ulz, Christian Windpassinger, Werner Wackernagel, Shea Loy, Ingrid Wolf, [......], Arno Rütten, Gabriele Palmedo, David Abramson, Kenneth Offit, Arthur Ott, Jürgen C Becker, Lorenzo Cerroni, Heinz Kutzner, Boris C Bastian, Michael R Speicher

  Nature genetics. 08/2011; 43(10):1018-21.

  Common acquired melanocytic nevi are benign neoplasms that are composed of small, uniform melanocytes and are typically present as flat or slightly elevated pigmented lesions on the skin. We describe two families with a new autosomal dominant syndrome characterized by multiple, skin-colored, elevate... [more] Common acquired melanocytic nevi are benign neoplasms that are composed of small, uniform melanocytes and are typically present as flat or slightly elevated pigmented lesions on the skin. We describe two families with a new autosomal dominant syndrome characterized by multiple, skin-colored, elevated melanocytic tumors. In contrast to common acquired nevi, the melanocytic neoplasms in affected family members ranged histopathologically from epithelioid nevi to atypical melanocytic proliferations that showed overlapping features with melanoma. Some affected individuals developed uveal or cutaneous melanomas. Segregating with this phenotype, we found inactivating germline mutations of BAP1, which encodes a ubiquitin carboxy-terminal hydrolase. The majority of melanocytic neoplasms lost the remaining wild-type allele of BAP1 by various somatic alterations. In addition, we found BAP1 mutations in a subset of sporadic melanocytic neoplasms showing histological similarities to the familial tumors. These findings suggest that loss of BAP1 is associated with a clinically and morphologically distinct type of melanocytic neoplasm.
• 6.26

  Impact points

  Combined molecular genetic and cytogenetic analysis from single cells after isothermal whole-genome amplification.

  Thomas Kroneis, Jochen B Geigl, Amin El-Heliebi, Martina Auer, Peter Ulz, Thomas Schwarzbraun, Gottfried Dohr, Peter Sedlmayr

  Clinical chemistry. 05/2011; 57(7):1032-41.

  Analysis of chromosomal aberrations or single-gene disorders from rare fetal cells circulating in the blood of pregnant women requires verification of the cells' genomic identity. We have developed a method enabling multiple analyses at the single-cell level that combines verification of the gen... [more] Analysis of chromosomal aberrations or single-gene disorders from rare fetal cells circulating in the blood of pregnant women requires verification of the cells' genomic identity. We have developed a method enabling multiple analyses at the single-cell level that combines verification of the genomic identity of microchimeric cells with molecular genetic and cytogenetic diagnosis. We used a model system of peripheral blood mononuclear cells spiked with a colon adenocarcinoma cell line and immunofluorescence staining for cytokeratin in combination with DNA staining with the nuclear dye TO-PRO-3 in a preliminary study to define candidate microchimeric (tumor) cells in Cytospin preparations. After laser microdissection, we performed low-volume on-chip isothermal whole-genome amplification (iWGA) of single and pooled cells. DNA fingerprint analysis of iWGA aliquots permitted successful identification of all analyzed candidate microchimeric cell preparations (6 samples of pooled cells, 7 samples of single cells). Sequencing of 3 single-nucleotide polymorphisms was successful at the single-cell level for 20 of 32 allelic loci. Metaphase comparative genomic hybridization (mCGH) with iWGA products of single cells showed the gains and losses known to be present in the genomic DNA of the target cells. This method may be instrumental in cell-based noninvasive prenatal diagnosis. Furthermore, the possibility to perform mCGH with amplified DNA from single cells offers a perspective for the analysis of nonmicrochimeric rare cells exhibiting genomic alterations, such as circulating tumor cells.
• 10.84

  Impact points

  Evolution of genomic instability in diethylnitrosamine-induced hepatocarcinogenesis in mice.

  Kristina Aleksic, Carolin Lackner, Jochen B Geigl, Martina Schwarz, Martina Auer, Peter Ulz, Maria Fischer, Zlatko Trajanoski, Marcus Otte, Michael R Speicher

  Hepatology (Baltimore, Md.). 03/2011; 53(3):895-904.

  Diethylnitrosamine (DEN) is a hepatic procarcinogen which is frequently used as an inducer of hepatocellular carcinoma (HCC) in mice. Although mice after DEN exposure are among the most widely used models for liver tumorigenesis, a detailed, mechanistic characterization of the longitudinal changes i... [more] Diethylnitrosamine (DEN) is a hepatic procarcinogen which is frequently used as an inducer of hepatocellular carcinoma (HCC) in mice. Although mice after DEN exposure are among the most widely used models for liver tumorigenesis, a detailed, mechanistic characterization of the longitudinal changes in the respective tumor genomes has never been performed. Here we established the chronological order of genetic alterations during DEN carcinogenesis by examining mice at different points in time. Tumor samples were isolated by laser microdissection and subjected to array-comparative genomic hybridization (array-CGH) and sequencing analysis. Chromosomal gains and losses were observed in tumors by week 32 and increased significantly by week 56. Loss of distal chromosome 4q, including the tumor suppressors Runx3 and Nr0b2/Shp, was a frequent early event and persisted during all tumor stages. Surprisingly, sequencing revealed that β-catenin mutations occurred late and were clearly preceded by chromosomal instability. Thus, contrary to common belief, β-catenin mutations and activation of the Wnt/β-catenin pathway are not involved in tumor initiation in this model of chemical hepatocarcinogenesis. CONCLUSION: Our study suggests that the majority of the current knowledge about genomic changes in HCC is based on advanced tumor lesions and that systematic analyses of the chronologic order including early lesions may reveal new, unexpected findings.
• 0.47

  Impact points

  Extra phenotypic features in a girl with Miller syndrome.

  Ali Al Kaissi, Katharina M Roetzer, Peter Ulz, Ellen Heitzer, Klaus Klaushofer, Franz Grill

  Clinical dysmorphology. 02/2011; 20(2):66-72.

  A 4-year-old girl, the child of nonconsanguineous parents was referred for clinical assessment because of postaxial limb defects associated with mild facial dysmorphism. The overall phenotypic features were compatible with the Miller syndrome. The proband manifested distinctive bone defects, consist... [more] A 4-year-old girl, the child of nonconsanguineous parents was referred for clinical assessment because of postaxial limb defects associated with mild facial dysmorphism. The overall phenotypic features were compatible with the Miller syndrome. The proband manifested distinctive bone defects, consisting of triangular-shaped terminal phalanges and cone-shaped epiphyses of the middle phalanges of the feet. Using the sequence analysis of the DHODH gene we identified compound heterozygous mutations in the proband. Furthermore, both the parents were found to be heterozygous carriers of one of the two mutations found in the proband. Interestingly, the father had a history of postaxial polydactyly. We speculated that the postaxial polydactyly in the father was either a heterozygote manifestation or is unrelated.
• 5.23

  Impact points

  Mapping of balanced chromosome translocation breakpoints to the basepair level from microdissected chromosomes.

  Anna C Obenauf, Thomas Schwarzbraun, Martina Auer, Eva M Hoffmann, Julie Waldispuehl-Geigl, Peter Ulz, Barbara Günther, Hans-Christoph Duba, Michael R Speicher, Jochen B Geigl

  Journal of cellular and molecular medicine. 08/2010; 14(8):2078-84.

  The analysis of structural variants associated with specific phenotypic features is promising for the elucidation of the function of involved genes. There is, however, at present no approach allowing the rapid mapping of chromosomal translocation breakpoints to the basepair level from a single chrom... [more] The analysis of structural variants associated with specific phenotypic features is promising for the elucidation of the function of involved genes. There is, however, at present no approach allowing the rapid mapping of chromosomal translocation breakpoints to the basepair level from a single chromosome. Here we demonstrate that we have advanced both the microdissection and the subsequent unbiased amplification to an extent that breakpoint mapping to the basepair level has become possible. As a case in point we analysed the two breakpoints of a t(7;13) translocation observed in a patient with split hand/foot malformation (SHFM1). The amplification products of the der(7) and of the der(13) were hybridized to custom-made arrays, enabling us to define primers at flanking breakpoint regions and thus to fine-map the breakpoints to the basepair level. Consequently, our results will also contribute to a further delineation of causative mechanisms underlying SHFM1 which are currently unknown.