96. Jahrestagung der Deutschen Gesellschaft für Pathologie e. V ...

AG Paidopathologie II
SO-046
Overexpression of co stimulatory ICAM1 enhances killing of RMS
cell lines by NKT and chimeric T cells
K . Simon-Keller 1 , A .-L . Bohlender 1 , K . Mößinger 1 , S . Küffer 1 , P . Ströbel 1 ,
A . Marx 1
1 University Medical Center Mannheim, Institute of Pathology, Mannheim
Aims. Rhabdomyosarcomas (RMS) are the most common soft tissue sarcoma
of childhood and adolescence. Recent efforts to enhance overall
survival of patients with clinically advanced RMS have failed. Different
types of immunotherapies have been suggested as new perspective.
However, little is known about immune escape mechanisms in RMS.
Killing of RMS cells with specific chimeric T (cTCs) and NKT cells was
markedly attenuated in comparison to killing of CEA-expressing colon
carcinoma cells by respective cTCs. Therefore, we wondered whether resistance
to killing might be due to lack of co-stimulatory molecules and
if so, whether it is possible to improve killing efficiency by overexpression
of defective co-receptors.
Methods. We compared four alveolar RMS cell lines and two embryonal
RMS cell lines with 16 embryonal and 12 alveolar RMS biopsies. Expression
status of different surface molecules was checked by FACS analysis,
Western blot, and qRT-PCR to characterize RMS cell lines. Biopsies were
analyzed by IHC, Western blot and qRT-PCR. Cell lines were transfected
with CD54 by electroporation and checked by FACS for CD54 surface expression.
Cell survival after co-cultivation of RMS and chimeric T cells
was checked by MTT test and FACS analysis.
Results. Studying expression levels of MHC class I, MHC class II, CD80,
CD86, ICAM-1/CD54 in RMS cell lines and biopsies we found low to
absent expression of crucial co-receptors, e.g. ICAM1 and CD86 both in
vitro and in vivo. To functionally prove the influence of ICAM-1 expression
on killing efficiency, we overexpressed ICAM1 in six RMS cell lines.
On co-incubation with cTC and NKT cells, all RMS cell lines showed
substantially increased susceptibility to cTC and NKT cell mediated killing
after overexpression of ICAM1.
Conclusions. The results imply that RMS cell lines lack expression of crucial
co-receptors for cytotoxic T cell responses. Up-regulation of ICAM
appears as promising strategy to enhance the cytotoxic effect of the immune
system against RMS cells, e.g. following RMS-directed vaccination
or adoptive transfer strategies.
SO-047
The role of homeobox genes in the development of nephroblastomas
K . Koller1 , M . Pichler2 , K . Koch1 , M . Zandl1 , I . Leuschner1 , G . Höfler1 , B . Gürtl1 1 2 Medical University of Graz, Institute of Pathology, Graz, Austria, Medical
University of Graz, Department of Internal Medicine, Graz, Austria
Aims. Different homeobox genes and some of their binding partners feature
already known tumorigenic properties, but their role in the pathogenesis
of nephroblastomas has hardly been investigated. In our study
we therefore focused on the expression of HOXA9 and its binding partners
in different subtypes of nephroblastomas.
Methods. The mRNA expression levels were investigated by quantitative
REALtime PCR, protein expression levels by immunohistochemistry.
Results. All nephroblastomas investigated so far had a significant upregulation
of MEIS1 mRNA expression levels. In parallel in most of these
cases a nuclear positivity with antibodies against MEIS1 was identified.
The majority of nephroblastomas investigated so far also showed an
overexpression of PBX2 mRNA, some of them additionally a distinct
positive nuclear staining in the immunohistochemical investigation. The
mRNA expression levels of HOXA9 were significantly higher in most of
the tumors investigated.
Conclusions. Our results show that the upregulation of homoebox genes
and their binding partners might play a role in the development of nephroblastomas.
SO-048
Gain of chromosome 8 and IGF1R in pleuropulmonary blastoma
C . Vokuhl1 , L . de Leon1 , S . Kirsch2 , E . Koscielniak2 , I . Leuschner1 1 2 University of Kiel, Department of Pediatric Pathology, Kiel, Olgaspital,
Klinikum Stuttgart, Pediatric 5
Aims. Pleuropulmonary blastoma (PPB) is a very rare, aggressive primary
intrathoracic tumor of early childhood. This tumor is composed
of a malignant mesenchymal component, namley a rhabdomyomatous,
chondroid or fibrosarcomatous, and an epithelial component regarded
as entrapped elements. Histopathologically, three different types are described:
Type 1 PPB is composed exclusively of cysts lined by a benign
epithelium. The cyst walls consist of small, malignant mesenchymal
cells, type 2 is composed of cystic and solid areas and type 3 is an entirely
solid tumor. The outcome is poor, with 5-years survival rates of 45-49%
and 66%, respectively. Because of the rarity of this tumor type, the genetics
are poorly understood.
Methods. In this study we want to analyse the PPB cases of the Kiel Pediatric
Tumor Registry. Sufficient DNA from 16 patients could be extracted.
We analysed these cases by comparative genomic hybridisation and
confirmed tumors with gain of chromosome 8 and of IGF1R by FISH.
Results. The most frequently recurring change was gain of chromosome
8 and the short arm of chromosome 8, respectively (9/17). Six pleuropulmonary
blastomas show gain of chromosome 20 (pq and p). Genomic
amplification was observed in 5 cases, four related to 15q25qter, and one
to 1p. We were able to perform Cen8 FISH in all but one of the cases with
chromosome 8 gain. Two tumors show trisomy of chromosome 8, 4 tumors
a polysomy (in average 4–5.8 signals per nucleus). The remaining
one showed normal signal pattern. FISH could confirm three low-level
amplifications and one high-level amplification of the IFG1R gene.
Conclusions. Pleuropulmonary blastoma is a very rare pediatric tumor,
therefore only case reports or small series of genetic studies were published.
In our series of 18 PPBs we could show a gain of chromosome 8 in
51% (9/17). In addition we found five amplifications, four of which are in
the 15q21qter region where the insulin-like growth factor type 1 (IGF1R)
gene (15q26) lies. All of these were pleuropulmonary blastomas type III,
indicating that it is a later event in tumor progression. In future we have
to correlate these results with prognosis and these findings suggest the
possibility of use of targeted agents in the therapy of a subset of these
rare tumors.
SO-049
Expression of cancer testis (CT) antigens in fetal thymus
A . Jungbluth1 , D . Frosina1 , M . Holz1 , G . Spagnoli 2 , S . Gnjatic1 , A .M . Müller3 1Ludwig Institute for Cancer Research, Memorial Sloan-Kettering Cancer
Center, New York, United States, 2University Hospital Basel, Department of
Biomedicine, Basel, Switzerland, 3University Bonn, Department of Pediatric
Pathology, Bonn
Aims. CT antigens such as NY-ESO-1, MAGE, GAGE, and CT7 are named
after their characteristic pattern of expression, since they are found
in various types of cancer and in normal adult tissues are restricted to
testicular germ cells. They are also present in fetal ovarian germ cells
and occasionally in placenta. In cancer patients, some CT antigens are
highly immunogenic and due to their limited expression in normal tissues,
are used as vaccine targets for the immunotherapy of cancer. They
also serve as markers of malignancy. Little is known about the biology
of CT antigens and especially their role in the normal immune system.
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