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

situation, the V600E mutation in the BRAF locus was observed in the
primary tumor and the later biopsies from the lung and brain implying
that different metastases may resemble different tumor subclones which
need to be analysed separately.
Conclusions. In conclusion, our observations point to a heterogeneous
BRAF mutation status i) during the time course of the disease, and ii) in
a very small subset of tumor cells in a given sample. These results highlight
the need for a critical therapy evaluation in which the this mutational
analysis of the BRAF gene target needs to be embedded in the overall
clinical setting rather then simply rely on a yes-or-no result of the mutational
test of a single biopsy. Thus, the whole setting has to be taken into
account by the pathologist, molecular biologist and clinician.
SA-P-057
Integrin expression in primary tumor and their brain metastasis
A . Vogetseder1 , S . Thies1 , M . Weller2 , P . Schraml1 , H . Moch1 1UnversitätsSpital Zürich, Clinical Pathology, Zürich, Switzerland,
2UnversitätsSpital Zürich, Neurology, Zürich, Switzerland
Aims. To determine the expression of avb3, avb5 and avb8 integrins in
breast, lung and kidney cancer as well as in malignant melanoma and
their brain metastases.
Methods. Novel subtype specific rabbit monoclonal antibodies for avb3,
avb5 and avb8 integrins. Immunohistochemistry on tissue microarrays.
Results. Integrin avb5 is predominantly expressed in all primary tumours
and their metastases. Negative or weak integrin avb3 and avb8
expression in primary lung, renal and breast cancers. Significant increase
of avb3 and avb8 expression in brain metastases. Primary malignant
melanoma and their brain metastases show varying amounts of avb3 and
avb8 expression.
Conclusions. Rabbit monoclonal antibodies allow the analysis of specific
integrin isoforms. The avb3 and avb5 inhibitor cilengitide could also, like
in glioblastoma treatment, be effective in patients with brain metastases
of melanomas as well as lung, breast and kidney carcinomas.
SA-P-058
Activating PDGFRA mutations in inflammatory fibroid polyps
occur in exons 12, 14 and 18 and are associated with tumour
localization
S . Huss1 , E . Wardelmann1 , D . Goltz2 , W . Hartmann1 , E . Binot1 , H . Löser1 ,
S . Merkelbach-Bruse1 , R . Buettner1 , H .-U . Schildhaus1 1 2 University Hospital Cologne, Institute of Pathology, Köln, University Hospital
Bonn, Institute of Pathology, Köln
Aims. Inflammatory fibroid polyps (IFP) are mesenchymal tumours of
the gastrointestinal tract. This study was performed to broaden the base
of evidence of the pathogenic role of PDGFR mutations in IFP.
Methods. A total of 38 IFP, extracted from our consultation files, were
included in this study. Clinicopathological features were collected and
mutational analysis was carried out.
Results. Activating mutations in three different exons of PDGFRA were
found in 25 IFP. For the first time we report two cases with PDGFRAexon
14 mutations (p.N659K; p.[N659K(+)T665A]). The results of our
study and cases reported earlier in the literature clearly indicate that
there is a localization specific pattern: exon 12 mutations predominate
in the small intestine, while exon 18 mutations frequently occur in the
stomach (p