Overexpression of HER2/neu oncoprotein in cytologic specimens.
OBJECTIVE
To assess the rate of HER2/neu overexpression in cytologic specimens by immunocytochemistry (ICC) and compare these results in matched surgical specimens by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), when available.


METHODS
All cytologic specimens processed for HER2/neu evaluation by ICC (72 cases) and available corresponding histologic specimens (16 cases) were retrieved from our files. ICC was applied to previously Papanicolaou stained, routine fine needle aspirations specimens (64 cases) and cytocentrifuged, alcohol-fixed, fluid specimens (8 cases). FISH was performed on 6 histologic specimens.


RESULTS
Overexpression of HER2/neu was seen in 7/22 breast cancers (31.8%), 3/18 pulmonary adenocarcinomas (16.6%), 2/5 colorectal adenocarcinomas (40%), 1/2 adenocarcinomas of the biliary system (50%), 1/3 thyroid papillary carcinomas (33.3%) and 1/3 prostate adenocarcinomas (33.3%). Sixteen cases had IHC in matched histologic specimens: 14 (87.5%) cases were concordant (11 negative and 3 positive in both specimens), 1 case was negative in the cytologic specimen and positive in the histologic specimen (with no amplification by FISH), and 1 case was positive in the cytologic specimen and negative in the histologic specimen (not informative by FISH).


CONCLUSIONS
Our data suggest that overexpression of HER2/neu oncoprotein can be successfully detected in routine cytologic specimens, providing a simple, fast and cost-effective method of selecting patients for specific treatment.
Mitteldorf
Cristina A
CA
Laboratory of Surgical and Molecular Pathology, Hospital Sírio Libanês, São Paulo, SP, Brazil. crismitteldorf@ig.com.br
Leite
Kátia R
KR
Meirelles
Maria Inês
MI
Gattas
Gilka J
GJ
Camara-Lopes
L H
LH
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000096:biosynthesis*; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D011237:Predictive Value of Tests; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000096:biosynthesis*; D015203:Reproducibility of Results; D015854:Up-Regulation / Q000502:physiology
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases