HER2/neu detection by immunohistochemistry: optimization of in-house protocols.
The assessment of HER2/neu status is performed to predict monoclonal antibody therapeutic (trastuzumab) responsiveness of invasive breast cancer. The determination is usually performed by immunohistochemistry (IHC), using commercial kits approved by the Food and Drugs Administration (FDA) or by in-house protocols. The authors evaluated HER2 expression using different IHC protocols, to obtain the most concordant results with the FDA-approved system. A tissue microarray paraffin block with 110 samples of several types of histologic specimens was built. On the basis of commercially available kit HercepTest, several protocol steps modifications were made and further compared with HercepTest results. HER2 protein expression was evaluated both semiquantitatively (0, 1+, 2+, 3+ scoring) and qualitatively (specificity and nonspecific background). The most reliable results (98.2% concordance; 0.9% of background) were obtained using a 1:800 primary antibody dilution (Dako-A0485), Tris/EDTA as antigen retrieval solution (Dako-S2367) and a polymer as detection system (EnVision). Tissue microarray controls provided an important contribution, ensuring a rapid and low cost way to standardize and optimize IHC, using in-house protocol, for HER2 expression detection. This in-house protocol for HER2 expression evaluation can be an efficient, specific, and accurate alternative to the FDA-approved kit in a more cost effective manner.
Lourenço
Hugo M
HM
Serviço de Anatomia Patológica, Instituto Português de Oncologia de Lisboa de Francisco Gentil, Lisboa, Portugal. hugolourenco.13@gmail.com
Pereira
Teresa P
TP
Fonseca
Ricardo R
RR
Cardoso
Paula M
PM
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods* / Q000592:standards; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000096:biosynthesis; D012680:Sensitivity and Specificity; D046888:Tissue Array Analysis; D000068878:Trastuzumab; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab