Evaluation of c-erbB-2 gene in breast cancer
by chromogenic in situ hybridization:
comparison with immunohistochemistry
Kounelis S, Kapranos N, Malamos N, Kokka E, Kouri-Bairaktari
E.
Dpt of Pathology, Elena Venizelou Hospital Dpt of Pathology,
Division of Molecular Pathology,
Amalia Fleming Hospital Athens, Greece
Aim: c-erbB-2 is of great importance for the
selection of patients with breast cancer who will receive therapy
with Herceptin. The purpose of this study is to evaluate c-erbB-2
gene status with the recently developed technique of chromogenic
in situ hybridization (CISH) and to compare the results with those
of immunohistochemistry.
Material and methods: Thirty three cases of
breast carcinoma from women 39-79 years of age, that underwent
mastectomy at Helena Venizelou Hospital and had an immunohistochemical
c-erbB-2 protein score of 1+, 2+ 3+ (HercepTestTM).
The evaluation of c-erbB-2 gene status was made on paraffin section
with the CISH technique and the application of a digoxygenin-labeled
DNA probe. Cases with 1-5 gene copies per nucleus were defined
as negative, 5-10 copies per nucleus as low level amplification
(LL) and 10-20 copies per nucleus as high level amplification
(HL).
Results:
| |
IHC -
|
IHC +
|
| CISH |
1+
|
2+
|
3+
|
| Non-Amplified |
8
|
9
|
0
|
| Amplified LL |
0
|
2
|
3
|
| Amplified HL |
1
|
2
|
8
|
| Concordance |
8/9 (89%)
|
4/13 (30%)
|
11/11 (100%)
|
Conclusion: Our results show that the discordance
rate was highest (70%) in the immunohistochemical 2+ group and
smaller (11%) in the 1+ group. Since recent studies indicate that
c-erbB-2 status may provide more precise information in relation
to Herceptin therapy response, the additional evaluation of c-erbB-2
gene status by CISH is considered necessary especially in the
2+ group.
Key words: Breast cancer, chromogenic in situ hybridization,
CISH, c-erbB-2.
|
