Effect of ischemic time, fixation time, and fixative type on HER2/neu immunohistochemical and fluorescence in situ hybridization results in breast cancer.
Accurate determination of HER2/neu status in breast carcinoma is essential. Alteration of preanalytic variables is known to affect HER2/neu results. American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) issued guidelines to standardize fixation for increased HER2/neu accuracy. We studied the effects of changing preanalytic variables on HER2/neu immunohistochemical and fluorescence in situ hybridization (FISH) results in a known HER2/neu+ invasive carcinoma. The clinical specimen was processed according to ASCO/CAP guidelines, with remaining tumor stored fresh without any fixatives for 4 days at 4°C and cut into core biopsy-sized pieces. Each was fixed in 10% formalin, 15% formalin, Pen-Fix (Richard-Allan Scientific, Kalamazoo, MI), Bouin solution, Sakura molecular fixative (Sakura Tissue-Tek Xpress, Torrance, CA), or zinc formalin for 0 to 168 hours. Immunohistochemical studies and FISH were performed. Compared with the clinical specimen, the samples showed no tumor degradation or marked difference by immunohistochemical studies, except the 1-hour 10% formalin and Bouin samples, or FISH, except the Bouin-fixed samples. Our study demonstrates that HER2/neu results remain accurate beyond ASCO/CAP-recommended preanalytic variables, with the exception of Bouin solution for FISH analysis.
Dept. of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California-Los Angeles, 10833 Le Conte Ave CHS, Los Angeles, CA 90095, USA.
Neda A
NA
Moatamed
Gouri
G
Nanjangud
Richard
R
Pucci
Alarice
A
Lowe
I Peter
IP
Shintaku
Saeedeh
S
Shapourifar-Tehrani
Nagesh
N
Rao
David Y
DY
Lu
Sophia K
SK
Apple
D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D005404:Fixatives; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D016707:Tissue Fixation / Q000379:methods*
D005404:Fixatives; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human