2009 Vienna - European Society of Human Genetics

Concurrent Sessions
genes to be recurrently affected, which strongly supports its role in
CRC predisposition.
c06.3
thetRim8 gene is a novel player of p53 pathway
L. Micale 1 , M. F. Caratozzolo 2 , A. M. D’Erchia 2 , M. G. Turturo 1 , B. Augello 1 , C.
Fusco 1 , P. Malatesta 3 , E. Sbisà 2 , A. Tullo 2 , G. Merla 1 ;
1 Medical Genetics Unit, IRCCS Casa Sollievo Della Sofferenza Hospital, San
Giovanni Rotondo, Italy, 2 Institute for Biomedical Technologies - C.N.R., Bari,
Italy, 3 National Institute for Cancer Research, Genova, Italy.
p53 helps to maintain genomic integrity, regulates the cell-stress response,
and controls human cancer development and progression.
Approximately half of all human malignancies carry mutant p53, and
many tumours containing wild-type p53 have abnormalities in p53
regulators.
By using a microarray based approach we found that p53 significantly
induces the expression of TRIM8, a gene belonging to the Tripartite
Motif (TRIM) protein family involved in various cellular functions such
as cell proliferation and differentiation. Bionformatic analysis, ChIP and
luciferase assays revealed that TRIM8 regulation is modulated by four
p53 responsive elements located in the first intron of TRIM8 gene.
Importantly, we showed that TRIM8 interacts with and increases the
p53 protein stability and it affects p53 transcriptional activation of p21
in mammalian cell lines.
TRIM8 is located within the 10q24.3, a region mostly involved in deletions
and rearrangements in brain cancer. By QPCR we showed
that the relative expression of TRIM8 is strongly underexpressed in a
number of human glioblastomas. MTT cell proliferation and colony formation
assays showed that the overexpression of TRIM8 inhibits cell
proliferation. Consistently, siRNA mediated TRIM8 silencing in mouse
neural progenitor cell cultures increases the normal cell cycle progression
suggesting that TRIM8 might be involved in a tumour suppression
mechanism.
Together these observations suggest the existence of a new p53-
TRIM8 feedback-loop mechanism and support the hypotheses that
TRIM8 might participate to the development of glioblastomas through
yet unknown molecular mechanisms that involve p53.
c06.4
Identification of Low Penetrance Genes associated to thyroid
cancer susceptibility using a two-step case-control approach
I. Landa 1 , S. Ruiz-Llorente 2 , C. Montero-Conde 2 , L. Leandro-García 1 , S.
Leskelä 1 , E. López-Jiménez 1 , A. Maliszewska 1 , L. Inglada-Pérez 1 , L. De La
Vega 1 , G. Pita 1 , M. Alonso 1 , J. Maravall 3 , V. Andía 4 , C. Álvarez-Escolá 5 , A.
Meoro 6 , J. Caballero 7 , C. Blanco 8 , J. Díaz-Pérez 9 , J. Serrano 10 , D. Mauricio 3 ,
A. Cascón 1 , C. Rodríguez-Antona 1 , A. González-Neira 1 , P. Santisteban 2 , M.
Robledo 1,11 ;
1 CNIO (Spanish National Cancer Research Centre), Madrid, Spain, 2 Biomedical
Research Institute (IIB, CSIC-UAM), Madrid, Spain, 3 Hospital Arnau de Vilanova,
Lleida, Spain, 4 Hospital General Universitario Gregorio Marañón, Madrid,
Spain, 5 Hospital Universitario La Paz, Madrid, Spain, 6 Hospital Universitario
Reina Sofía, Murcia, Spain, 7 Hospital Reina Sofía, Córdoba, Spain, 8 Hospital
Universitario Príncipe de Asturias, Alcalá de Henares, Spain, 9 Hospital Clínico
San Carlos, Madrid, Spain, 10 Hospital General Universitario de Alicante, Alicante,
Spain, 11 ISCIII Center for Biomedical Research on Rare Diseases (CI-
BERER), Spain.
Papillary Thyroid Carcinoma (PTC) is believed to have a strong genetic
component, as suggested by the high relative risk (8.6-fold) reported
for first-degree relatives of probands. However, no high penetrance
gene related to PTC has been described so far. The aim of this study
was to identify low penetrance genes (LPG) that could explain the individual
susceptibility.
We have selected candidate genes according to the following criteria:
(i) their relevant role in biological pathways related to thyroid cell differentiation
and proliferation and (ii) their differential expression profile,
as observed in our own set of representative samples of thyroid carcinoma.
Through this process, 97 genes, tagged by 768 SNPs, were included.
SNPs were chosen through different SNPs databases (NCBI,
HapMap) and in silico tools (Pupa Suite) to include Tag SNPs and
putative functional SNPs when possible. These SNPs were genotyped
in a two step case-control study. In a first stage, we genotyped more
than 600 PTC Spanish patients versus more than 500 representative
healthy controls, using the Illumina Sentrix Array platform. Associa-
tion tests were performed on single SNPs and haplotypes to define
susceptibility PTC loci. Top ten SNPs are currently being validated by
KASPar probes in a second stage of the study that includes an Italian
series of more than 400 patiens and over 500 controls.
At this moment, we have identified, at least three putative LPG related
to thyroid cancer susceptibility. Functional validation is also being performed
for two of these loci.
c06.5
Detection of tumor-specific somatic mutations by transcriptome
sequencing of a cytogenetically normal acute myeloid leukemia
S. H. Eck 1 , P. A. Greif 2,3 , A. Benet-Pagès 1 , H. Popp 2 , A. Dufour 2 , T. Meitinger 1,4 ,
T. M. Strom 1,4 , S. K. Bohlander 2,3 ;
1 Helmholtz Zentrum München, Institue of Human Genetics, Munich, Germany,
2 Department of Medicine III, Universität München, Munich, Germany, 3 Clinical
Cooperative Group “Leukemia”, Helmholtz Zentrum München, German Research
Center for Environmental Health, Munich, Germany, 4 Institute of Human
Genetics, Technische Univeristät München, Munich, Germany.
Approximately half of acute myeloid leukemia (AML) patients have at
least one chromosomal aberration, whereas the other half classifies
as cytogenetically normal (CN-AML). Most of the genetic events that
initiate the disease are still undiscovered.
To identify tumor-specific somatic coding mutations, we sequenced
the transcriptome of a CN-AML and a matched remission sample by
second-generation sequencing technology (Illumina GAII). SNPs were
called with the MAQ software. Additional filters were applied to exclude
known and possible sequencing artefacts.
We generated 20.4 and 15.6 million 32 bp paired-end reads of the
CN-AML and remission sample, respectively, which mapped to exons
of UCSC genes. 8.9% of reads for the AML and 5.0% reads of the remission
sample mapped to intergenic regions. Of the 11178 transcripts
with a higher expression than 60 reads per gene (corresponding to approximately
1 transcript per cell), we sequenced 5911 with an average
coverage of greater than seven. By comparing the 63159 SNPs discovered
in the CN-AML sample with the respective results in the remission
sample, we identified 5 non-synonymous mutations not present in
either the remission sample or in dbSNP. Among them is a nonsense
mutation affecting the RUNX1 gene, which forms a well known fusion
gene in AML (RUNX1/RUNX1T1). The other 4 mutations were missense
mutations which need further confirmation. Two of these were
in tumor-associated genes (TLE4, FOSB). These results demonstrate
that our technique of transcriptome sequencing is an efficient method
to discover new mutations in AML.
c06.6
ikaros is a frequently affected hematopoietic differentiation
factor in pediatric relapse-prone precursor B-cell acute
lymphoblastic leukemia
E. Waanders1 , M. W. M. te Loo2 , F. N. van Leeuwen2 , V. H. J. van der Velden3 ,
S. V. van Reijmersdal1 , J. de Vries3 , S. T. M. Keijzers-Vloet1 , J. Y. Hehir-Kwa1 ,
E. Sonneveld4 , J. J. M. van Dongen3 , A. Geurts van Kessel1 , P. M. Hoogerbrugge2,4
, R. P. Kuiper1 ;
1Department of Human Genetics, Radboud University Nijmegen Medical Center,
Nijmegen, The Netherlands, 2Department of Pediatric Hemato-Oncology,
Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands,
3Department of Immunology, Erasmus University, Rotterdam, The Netherlands,
4Dutch Childhood Oncology Group, The Hague, The Netherlands.
Relapse is the most common cause of treatment failure in childhood
acute lymphoblastic leukemia (ALL), but is difficult to predict in the majority
of cases. To explore the prognostic impact of recurrent genomic
abnormalities on relapse in children diagnosed with precursor-B cell
ALL, we have performed genome-wide copy number profiling of 34
paired diagnosis-relapse samples. Results were validated using locusspecific
copy number screening in 200 diagnosis samples of children
with or without relapse.
The majority of the copy number abnormalities were preserved between
matched diagnosis and relapse samples, but lesions unique in
either of the two samples were observed in 82% of the cases. In 68%
of the cases, lesions present at diagnosis were no longer detected in
relapse samples indicating that these lesions were secondary events,
absent in the original therapy-resistant progenitor clone. However, lesions
in IKZF1, which encodes the hematopoietic differentiation factor
Ikaros, were always preserved in relapse. Sequence analysis revealed