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

Abstracts
Methods. Tumor-DNA was extracted from 4–10 µM thick specimen slides
of formalin-fixed and paraffin-embedded tissue after micro dissection.
These probes were amplified with conventional PCR and checked
with agarose-gel-electrophoresis. The mutation status was assessed by
direct DNA sequencing.
Results. 61 intramuscular myxomas were examined and a mutation rate
of 36.07% (22 cases) was detected which correlate with data from published
studies. 75.41% of these were found in women. Both hotspots were
equally affected. Furthermore 26 other tumor entities (angiomyxomas/fibromas,
fibromyxoid sarcomas, chondrosarcomas, liposarcomas, FD,
lipomas and neurothekeomas) were analyzed. In 5 out of 8 FDs (62.5%),
mutations in codon 201 were discovered. In all other entities including
7 atrial myxomas and 31 gastroenteropancreatic-neuroendocrine tumors
(GEP-NET’s) no GNAS-1 mutations were detected.
Conclusions. Our results indicate that the GNAS-1 mutation analysis can
be helpful to differentiate between FD and unspecific bone lesions (e.g.
cystic or inflammatory conditions). It may be particular useful in the
differential diagnosis of myxoid tumors. GNAS-1 mutations were never
detected in any sarcomatous lesions while carrying a considerable prevalence
in intramuscular myxoma. Mutation-positive patient might be
screened for bone lesions compatible with FD to exclude Mazabraud’s
syndrome.
FR-P-178
Valproic acid stimulation induces downregulation of IRAK-1 protein
in a progressive thyroid carcinoma cell line
S . Schwertheim1 , S .-Y . Sheu-Grabellus1 , K . Worm1 , K .W . Schmid1 1University Hospital of Essen, University of Duisburg-Essen, Institute of
Pathology and Neuropathology, Essen
Aims. Valproic acid (VPA) is a drug in clinical phase 2 for the therapy
of advanced/poorly differentiated thyroid cancer with poor prognosis.
miRNA-146a/b has been proved to be deregulated in thyroid carcinoma.
To clarify if miRNA-146a/b plays a role in cells influenced by VPA
we treated the highly progressive thyroid cell line BHT-101 with various
doses of VPA (0, 1.0, 1.5 and 3.0 mM) and analyzed the expression levels
of these miRNAs. As it is documented that miRNA-146/b is associated
with regulation of NF-κB activity we also examined VPA-treated cells on
mRNAs and proteins modulated by NF-κB.
Methods. Cells were seeded in 6-well plates at 60–80% confluence and
incubated with VPA for 48 h; conditioned medium was used for treatment
containing 0.2% FCS, 1% Penicillin and 0.1% Amphotericin B.
miRNA and mRNA expression levels were detected by RT-PCR using
Taq Man miRNA- and Gene Expression-Assays (Applied Biosystems).
Protein analysis was performed by Western blotting.
Results. miRNA-146a/b was upregulated at a concentration of 1 mm
(foldchange 2.35) and 1.5 mM (foldchange 3.43) VPA and decreased at
3.0 mM (foldchange 2.26). VPA significantly and dose-dependently impaired
NF-κB activity, reducing expressions of IRAK-1 (miRNA-146a/b
target gene), phospho-IκBα and p50 protein. Remarkably, 1 mm VPA
treatment induced upregulation of IL-6 and IL-8 mRNA levels, following
reduced expressions at 3.0 mM; examination of IL-8 protein levels
confirmed this.
Conclusions. Our results suggest that miRNA-146a/b and IRAK-1 levels
play a crucial role in VPA’s mechanisms of action and might be promising
tools to regulate the therapy of advanced thyroid cancer.
140 | Der Pathologe · Supplement 1 · 2012
FR-P-179
Dysregulation of miRNA expression in normal thyroid tissue
adjacent to tumor cells
S . Schwertheim1 , S .-Y . Sheu-Grabellus1 , K . Worm1 , K .W . Schmid1 1University Hospital of Essen, University of Duisburg-Essen, Institute of
Pathology and Neuropathology, Essen
Aims. The miRNAs 146a, -146b -181b, -21, -221, -222, 30d, -125b, -26a, -30a-
5p, and -let7c have been proved to be deregulated in thyroid carcinoma.
To clarify if miRNAs can be used to evaluate tumor progression we analyzed
the expression of these miRNAs in 5 normal thyroid tissues adjacent
to highly progressive thyroid carcinomas (4 poorly differentiated, 1
anaplastic thyroid carcinoma) and compared the results with expression
levels in 4 normal thyroid tissues of individuals without any clinical thyroid
disease.
Methods. Paraffin embedded tissues were laser microdissected (PALM
Laser-Micro Beam System, P.A.L.M., Bernried) for RNA analysis. miR-
NA expression levels were detected by RT-PCR using Taq Man miRNA
assays and relative quantification of miRNA expression was calculated
with the 2-ΔΔCt method.
Results. We found significantly (p