Chromogenic in situ hybridization analysis of HER-2/neu status in cytological samples of breast carcinoma.
The current use of humanized monoclonal antibody trastuzumab for the treatment of patients with metastatic breast cancer has made evaluation of HER-2/neu status an important clinical issue. Chromogenic in situ hybridization (CISH), in which the DNA probe is detected with an immunohistochemistry (IHC)-like peroxidase reaction, has been recently developed for the assessment of HER-2/neu status in formalin-fixed breast cancer specimens. We have applied the technique of dual-colour CISH using HER-2/neu and chromosome 17 centromere probes in 27 cytological smears, and these cytological samples were obtained from scrapings of fresh breast tumours. We also investigated HER-2/neu amplification and protein overexpression in the corresponding surgical tissues by CISH and IHC using the monoclonal antibody CB11. Of the 27 cytological cases, HER-2/neu gene amplification was observed in nine cases that were positive cases (2+ and 3+) for IHC. Among the 13 IHC positive cases (2+ and 3+), four of them showed no gene amplification. Identical results for the CISH technique were obtained in the matched surgical samples. The scrape samples from fresh breast tumour offer a monolayer cell population that is especially suitable for CISH. This study has shown that the cytological smear might be a good alternative for the CISH test.
Kim
G Y
GY
Department of Pathology, Gachon Medical School Gill Medical Center, Incheon, Korea.
Oh
Y L
YL
D001706:Biopsy; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D002503:Centromere / Q000235:genetics; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D005260:Female; D005784:Gene Amplification / Q000235:genetics; D016591:Histocytological Preparation Techniques / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000235:genetics*
D018719:Erb-b2 Receptor Tyrosine Kinases