Immunocytochemistry and fluorescence in situ hybridization in HER-2/neu status in cell block preparations.
OBJECTIVE
Recent studies have validated the use of cytologic materials to determine HER-2/neu status. Good concordance has been shown between results obtained by immunocytochemistry (ICC), immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) on cytologic and surgical specimens. However, the utility of cytologic cell block material in determining HER-2/neu status has not been reported and is the subject of this study.


METHODS
HER-2/neu status was determined in 25 cases of primary or metastatic breast carcinoma by IHC and FISH. All cases were formalin-fixed, paraffin-embedded (FPPE) cell block preparations. ICC was performed using monoclonal antibodies TAB250 (Zymed) and CB11 (Novacastra Laboratories). FISH analysis was performed using the PathVysion HER-2 probe kit (Vysis, Inc.). Results of ICC and FISH were compared in each case.


RESULTS
Of 25 cases studied, 17 showed no protein overexpression or amplification. Five cases showed protein overexpression and amplification. The remaining 3 cases showed 2+ staining intensity by ICC in 10, 20, and 50% of carcinoma cells, respectively, and all demonstrated lack of amplification.


CONCLUSIONS
Immunocytochemistry performed on FFPE cell block material is a reliable method for determining HER-2/neu status in cytologic specimens. We recommend routine preparation of FFPE cell block material in instances of suspected primary of metastatic breast carcinoma.
Shin
Sandra J
SJ
Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, New York 10021, USA. sjshin@med.cornell.edu
Chen
Beiyun
B
Hyjek
Elizabeth
E
Vazquez
Madeline
M
D001943:Breast Neoplasms / Q000473:pathology; D003584:Cytological Techniques / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D009362:Neoplasm Metastasis; D010534:Peritoneal Neoplasms / Q000473:pathology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*
D018719:Erb-b2 Receptor Tyrosine Kinases