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

Abstracts
FR-P-107
Comprehensive histological characterization of murine hepatocellular
tumors – towards a classification of murine and human
hepatocellular carcinomas
L . Frick 1 , F . Böhm 2 , Y . Boege 1 , J . Friemel 2 , M . Heikenwaelder 3 , A . Weber 2
1 University Zurich, Department of Pathology, Zürich, Switzerland, 2 University
Zurich, Institute of Surgical Pathology, Zürich, Switzerland, 3 Munich,
Institute for Virology and Helmholtz Zentrum, München
Aims. The aim of our study is to characterise and compare different mouse
models of hepatocellular carcinoma (HCC) which may reflect different
ways of hepatocarcinogenesis in humans (including viral and toxic)
in order to test their applicability to human HCC.
Methods. We have implemented high-throughput, high-quality scanning
technology to make digital copies of all our histological slides. A
viewing software is used to display sequential sections side-by-side on a
computer screen, and to measure tumours and annotate them for later
reference. This enables us to determine the morphological and immunohistochemical
characteristics of each individual lesion efficiently and
comprehensively, even if there are many tumours and dysplastic lesions
per slide, and thus discover correlations that may otherwise have been
missed.
Results. We have found clear differences among the mouse models, not
only in the underlying liver pathology, but also in the spectrum of liver
tumours that arises. In addition, certain regularities and correlations of
tumour morphology and immunophenotype suggest a possible classification
of liver tumours in mice. Using tissue microarrays of human
HCC, we have discovered that the classification of murine tumours has
cross-species applicability to human tumours.
Conclusions. The results of our morphological and immunophenotypic
studies, together with the data from molecular analyses, provide
the basis for a classification of liver tumours that applies to both mice
and humans. We also intend to show which mouse models recapitulate
which aspects of hepatocarcinogenesis in humans, and may thus provide
suitable models for testing therapeutic interventions.
FR-P-108
LGR5 is differentially expressed in hepato-gastrointestinal
tumors
E . Simon1 , D . Petke1 , C . Böger1 , V . Warneke1 , H .-M . Behrens1 , C . Röcken1 1Christian-Albrechts-University, Institute of Pathology, Kiel
Aims. Carcinomas of the hepato-gastrointestinal tract are still leading
cause of cancer related deaths worldwide. The orphan G-protein-coupled
receptor (GPCR) and Wnt-target protein LGR5 was recently identified
as a stem cell marker for cells with intestinal differentiation. In
this study we generated a polyclonal anti-LGR5 antibody to investigate
protein expression in various hepato-gastrointestinal carcinomas and its
correlation with clinicopathological patient characteristics.
Methods. Differential expression of LGR5 was studied on transcriptional
(real time-polymerase chain reaction) and translational level (immunohistochemistry)
in carcinomas and corresponding normal mucosal specimens
comprising seven different primary tumor sites, i.e. oesophagus,
pancreas, stomach, liver, colon and rectum. The putative clinicopathological
relevance of LGR5 expression in terms of patient survival and the
histoanatomical distribution of the protein was studied in 100 patients
with gastric carcinoma.
Results. We succeeded to establish and characterize a highly specific antibody
that recognizes the C-terminal tail of LGR5. LGR5 was differentially
expressed on transcriptional and translational level in adenocarcinomas
of the oesophagus, pancreas, stomach, colon, rectum, hepatocellular
and cholangiocellular carcinoma of the liver compared with the adjacent
non-neoplastic tissue. However, in intestinal type gastric cancer the localization
and number of LGR5+ cells changed during tumorigenesis.
118 | Der Pathologe · Supplement 1 · 2012
Conclusions. Our results substantiate the significance of LGR5 on the biology
of hepatogastrointestinal carcinomas and provide evidence for its
function as potential stem cell marker and candidate therapeutic target
in the stomach. The strikingly changed histoanatomical distribution of
LGR5+ cells during tumorigenesis could be an important observation in
understanding tumor formation and progression. With our anti-LGR5
antibody we now have a useful tool for detection and further analyzes of
LGR5 biological function.
FR-P-109
Gene expression analysis of the Mcl-1delHEP mouse model of
hepatocarcinogenesis reveals overlapping expression profiles
with human hepatocellular carcinoma
F . Böhm1 , Y . Böge2 , R . Maire2 , J . Friemel1 , M . Heikenwälder3 , A . Weber1 1University Hospital Zurich, Institute of Surgical Pathology, Zürich, Switzerland,
2University Hospital Zurich, Institute of Neuropathology, Zürich,
Switzerland, 3Institute of Virology, Helmholtz Center, Munich
Aims. Apoptosis is regulated by a counterbalancing network of proapoptotic
and pro-survival proteins. Mcl-1 is a crucial pro-survival factor,
preventing cells to undergo apoptosis. Many chronic liver diseases
are characterized by a constant loss of hepatocytes. Recently, we have
shown that a mouse model with hepatocyte-specific deletion of Mcl-1
(Mcl-1delhep) reveals increased apoptosis, regeneration, and development
of hepatocellular carcinomas (HCC). To better characterize apoptosis-driving
tumorigenesis, we analyse gene expression patterns in the
Mcl-1delhep model, and compare these to gene expression patterns in
human liver tissues including HCC.
Methods. RNA from livers of Mcl-1delhep mice, several other genetic
mouse models and human HCCs of various etiologies were isolated,
analysed and compared by quantitative real-time PCR.
Results. RNA microarray of livers at 2 months of age uncovered significantly
up- and downregulated genes in Mcl-1delhep mice compared to
wild-type mice. Expression of Top 5 genes was also found to be significantly
upregulated in 12 months old Mcl-1delhep mice (non-tumor and
tumor tissue) and HCCs of various genetic mouse models for hepatocarcinogenesis
as well as in human liver RNA from HCCs with different
etiology.
Conclusions. The Mcl-1delhep mouse model shows that increased apoptosis
might serve as a main trigger of tumorigenesis, and thus recapitulates
the human pathogenesis of chronic liver diseases such as liver
tissue destruction and subsequent cancer formation. Overlapping gene
expression patterns in the Mcl-1delhep mouse model, human tissues of
chronic liver diseases and HCC confirms that the Mcl-1delhep mouse
model is a valuable tool for studying human hepatocarcinogenesis, and
thus also might be suitable for the identification of new molecular targets
and interventional studies.
FR-P-110
Clear cell foci of altered hepatocytes in human liver show an overexpression
of the AKT/mTOR and Ras/Raf1 pathways as well as the
lipogenic phenotype (similar to hepatocarcinogenesis in the rat
and to human hepatocellular carcinoma)
S . Ribback1 , D .F . Calvisi1 , C .-D . Heidecke2 , M . Birth3 , F . Dombrowski1 1 2 Universitätsmedizin Greifswald, Institut für Pathologie, Greifswald, Universitätsmedizin
Greifswald, Klinik und Poliklinik für Chirurgie, Greifswald,
3Hanse-Klinikum Stralsund, Klinik für Allgemein-, Viszeral-, Thorax- und
Gefäßchirurgie, Stralsund
Aims. AKT/mTOR and Ras/Raf1 pathways as well as the lipogenic phenotype
have been shown to be activated in a model of hepatocarcinogenesis
in the rat induced by hyperinsulinemia and in human hepatocellular
carcinomas. In the rat model the activation of these pathways starts