Related Experiment Video
Updated: Jan 24, 2026
Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy
Published on: September 11, 2015
Adherence to human epidermal growth factor receptor-2 testing and adjuvant trastuzumab treatment guidelines in
Deborah A Marshall1,2,3,4, Ilia L Ferrusi1,2,4, Maureen Trudeau4,5,6
1Centre for Evaluation of Medicines, St. Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada.
Objectives:
We evaluated adherence of human epidermal growth factor receptor-2 testing using immunohistochemistry and fluorescence in situ hybridization, as well as adjuvant trastuzumab treatment according to Canadian guidelines, and predictors of trastuzumab use in early-stage breast cancer in Ontario.
Methods:
Retrospective cohort of early-stage breast cancer patients identified in the Ontario Cancer Registry. Human epidermal growth factor receptor-2 test type, sequence, result(s), tumor grade, and hormone receptor status were abstracted from Ontario Cancer Registry pathology reports. Trastuzumab treatment was determined from provincial cancer agency records. Other variables were determined from administrative data sources. Logistic regression models were used to estimate adjusted odds ratios for factors associated with guideline adherence.
Results:
The first human epidermal growth factor receptor-2 test result was the strongest predictor of confirmatory testing (p < 0.05). Human epidermal growth factor receptor-2 testing by immunohistochemistry accounted for the majority of documented first tests (94%; n = 8249). Overall, 27% (n = 2360) of tested patients received a second test by fluorescence in situ hybridization (46%) or immunohistochemistry (49%) assay. Most human epidermal growth factor receptor-2 equivocal patients (89%; n = 784) received a confirmatory test. Among human epidermal growth factor receptor-2-positive patients, only 57% (n = 385) received trastuzumab treatment within the study period. Human epidermal growth factor receptor-2 status was the strongest predictor of trastuzumab use. Younger patients (<70 years at diagnosis) and negative hormone receptor status had higher odds of trastuzumab treatment (p < 0.05) compared to older and positive hormone receptor status patients.
Conclusions:
Immunohistochemistry use as a first test was largely consistent with Canadian guidelines; however, immunohistochemistry was frequently used as a confirmatory test, which is not guideline-concordant. Monitoring these testing and treating patterns is necessary to optimize health outcomes associated with trastuzumab.
More Related Videos
08:28Validated Immunochemical Assay for Comprehensive Determination of the Human Epidermal Growth Factor Receptor 2 Released from and Bound to Cells
Published on: May 9, 2025
21:16An In Vitro Skin Irritation Test SIT using the EpiDerm Reconstructed Human Epidermal RHE Model
Published on: July 13, 2009
Related Concept Videos
01:28Role of Hematopoietic Growth Factors
Thrombopoietin (TPO), mainly released by the liver,...
01:29Factors Influencing Microbial Growth: pH
01:27Factors Influencing Microbial Growth: Temperature
01:28Factors Influencing Microbial Growth: Osmolarity
01:18Treatment for Pulmonary Arterial Hypertension: Endothelin Receptor Antagonists
ETs are synthesized through a complex sequence of enzymatic steps, primarily involving an enzyme referred to as endothelin-converting enzyme...
01:23Treatment for Pulmonary Arterial Hypertension: Prostacyclin Receptor Agonists
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...