Transcript Diapositiva 1

HER-2/neu status in human
pancreatic adenocarcinoma:
comparative study of expression,
amplification and aneuploidy.
Truini M1, Ferro P2,3, Boccardo S1, Bacigalupo B2,
Salvi S1, Franceschini MC2,4, Gorji N2, Dessanti P2,
Pistillo MP5, Roncella S2, Fedeli F2.
1S.C.
Anatomia e Citoistologia Patologica, Istituto Nazionale per
la Ricerca sul Cancro, (IST); Genova.
2S.C. Anatomia ed Istologia Patologica e Citodiagnostica, ASL5
Spezzino, La Spezia.
3AIL “Sez. Francesca Lanzone”, La Spezia.
4Comitato Assistenza Malati e Lotta contro i Tumori, Sarzana
(SP).
5S.C. Genetica dei Tumori (Lab. Tumori Mammari), IST,
Genova.
Background
Pancreatic adenocarcinoma (PAC) is one of the
most lethal cancer in Italy and in western
countries. Therefore, the development of novel
therapeutic strategies for PAC is a main focus of
current investigations.
Trastuzumab recombinant monoclonal antibody
is widely used for the treatment of patients with
metastatic breast cancer that over-expresses
HER-2/neu oncogene.
The same therapy could be proposed also for
PAC because gene amplification and overexpression of Her-2/neu have been described in a
variety of cases, although with controversial
results.
Aim
The purpose of this study was to
evaluate, at protein and genomic level,
the status of HER-2/neu in PAC and to
correlate it with biological markers of
tumours.
Materials and Methods 1
To investigate the HER-2/Neu status in PAC we analyzed
45 paraffin-embedded tissue sections from PAC patients,
16 of which were primary tumours (10 with nodal
metastasis), 19 from hepatic metastasis and 10 from
metastatic lymph nodes at initial diagnosis.
Correlation between HER-2/neu status with stage, grade
and expression of Ki-67 (Mib-1) proliferation index was
also investigated.
Materials and Methods 2
HER-2/neu protein expression was analysed by
immunohistochemical staining (IHC) of p185 membrane
protein using the 4B5 monoclonal antibody. Antigens were
localized by means of a Ventana Medical System/ultra
viewTM DAB detection kit and the immunostaining was
performed
using
an
automated
Immunostainer
BenchmarkXT (Ventana Medical Systems, S. A. Strasbourg,
France).
Gene status (amplification of HER-2/neu and poliploidy of
chromosome 17, Chr.17) was analyzed by Fluorescente In
Situ Hybridization (FISH) (kit Pathvysion, Vysis - Abbott).
SpectrumOrange fluorescent-labeled probe specifically
hybridizes to the HER-2/neu gene locus and
SpectrumGreen fluorescent-labeled probe specifically
hybridizes to the centromeric region of Chr. 17.
Results
Our results showed over-expression of p185 membrane
protein in 11/45 (24.4%), gene amplification in 2/45 (4.4%)
and aneuploidy of Chr.17 in 6/45 (13.3%) of cases studied
respectively (Tab.1).
Over-expression of p185 was found in 3/16 (18.7%) primary
tumours (2/6 PAC without lymph node infiltration and 1/10
PAC with lymph node infiltration) (Tab.2, Fig.1) and in 8/19
(42.1%) hepatic metastatic lesions (Tab.3, Fig.2).
Amplification of the Her-2/neu oncogene was restricted to the
hepatic metastatic lesion (2/19, 10.5%) (Tab.3, Fig.2).
At last, Chr.17 aneuploidy was found in 4/19 (44.4%) hepatic
metastasis (Tab.3, Fig.2) and in 2/10 (20.0%) metastatic
lymph nodes (Tab.4, Fig.3).
No association was found between Her-2/neu status and
tumour stage, grade or Ki-67 cycling index.
Table 1. Summary of HER-2/neu status in PAC.
Positive cases (%)
n° of
cases
p185
Over-expression
HER-2/neu
Amplification
Chr. 17
Aneuploidy
45
11 (24.4)
2 (4.4)
6 (13.3)
Table 2. Summary of HER-2/neu status in primary PAC.
n° of
cases
16
Positive cases (%)
p185
HER-2/neu
Over-expression
Amplification
3 (18.7)
0 (00.0)
Chr. 17
Aneuploidy
0 (00.0)
Figure 1. Expression of p185 in a representative case of
PAC without genetic alteration.
HE
IHC
FISH
Table 3. Summary of HER-2/neu status in hepatic metastasis
of PAC.
n° of
cases
19
Positive cases (%)
p185
HER-2/neu
Over-expression
Amplification
8 (42.1)
2 (10.5)
Chr. 17
Aneuploidy
4 (44.4)
Figure 2. Expression of HER-2/neu in a representative case
of hepatic metastasis of PAC that shows over-expression of
p185 and amplification of HER-2/neu gene.
HE
IHC
FISH
Table 4. Summary of HER-2/neu status in PAC cells of
metastatic lymph node.
n° of
cases
10
Positive cases (%)
p185
HER-2/neu
Over-expression
Amplification
0 (00.0)
0 (00.0)
Chr. 17
Aneuploidy
2 (20.0)
Figure 3. Aneuploidy of Chr. 17 in a representative case
of metastatic limph node.
HE
IHC
FISH
Conclusions
• Our study confirms that a subset of PAC was
characterized by amplification of HER-2/neu gene
or aneuploidy of Chr.17, both associated/or not
to the over-expression of p185.
• HER-2/neu gene amplification was mainly
related to recurrent metastasis rather than to
primary tumours and over-expression of p185
was not always associated to genetic alterations.
• The use of Trastuzumab may find clinical
application in the targeted therapy of PAC with
over-expression of p185 or amplification of HER2/neu gene.