Identification of HER-2/neu Protein Expression in the Breast Cancer
Skálová A., 3Vaněček T., 4Lošan F., 4Papoutsidesová, 5Fínek J.
1Patologicko-anatomický ústav LF UK, Plzeň 2Bioptická laboratoř s.r.o., Plzeň 3Patologicko-anatomický ústav, Laboratoř speciální diagnostiky FN, Plzeň 4Genetická ambulance s laboratoří, Plzeň 5Radioterapeutické a onkologické oddělení FN, Plzeň |
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Summary:
Background. HER-2/neu protein overexpression has been shown to be an independently adverse prognostic and
predictive factor in patients with breast cancer. Recently, HER-2/neu overexpression has gained therapeutic
implications: It has been shown that in patients with breast cancer the use of trastuzumab/HerceptinTM, the
recombinant humanized monoclonal antibody directed against extracellular domain of HER-2/neu molecule, can
block the HER-2/neu protein activation and bring about a clinical remission. Following these developments, demand
for pathologists to evaluating properly HER-2/neu in breast cancer specimens has been rapidly increasing.
Methods and Results. In our series of 449 cases of breast cancer, HER-2/neu protein and gene were examined by
means of immunohistochemistry and fluorescence in situ hybridization respectively. Results of HER-2/neu study
were compared with the hormonal status, cancer grade and proliferation activity as assessed using immunohistochemistry
with MIB1 antibody. All seven cases of breast cancer with strong overexpression of HER-2/neu (score 3+)
manifested a gene amplification. In contrast, among 11 cases of breast cancers with mild HER-2/neu overexpression
(score 2+), the gene amplification was demonstrated in 5 cases only (45 %).
Conclusions. Immunohistochemical assessment and fluorescence in situ hybridization (FISH) are complementary
methods for detection of HER-2/neu status in breast cancer. While immunohistochemistry is an excellent screening
method, FISH should be used for the confirmation of positive results before the Herceptin treatment.
Key words:
breast cancer, HER-2/neu, oncoprotein cerbB2, immunohistochemistry, FISH.
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