Dr. Fernandez on the Results of a Study Examining Low HER2 Expression in Breast Cancer

Aileen I. Fernandez, PhD, postdoctoral fellow, Yale School of Medicine, discusses the results of a study examining low HER2 expression in breast cancer.

During a poster session at the 2021 San Antonio Breast Cancer Symposium, findings from a study evaluating low HER2 expression in patients with breast cancer were presented. In both cohorts analyzed, the analysis revealed a discrepancy between the frequency clinicians agreed upon immunohistochemistry (IHC) results of 0 vs 1+ or 2+ vs 3+. Moreover, clinicians were more likely to agree upon diagnoses of IHC 2+ or 3+ compared with 0 or 1+, Fernandez explains.

These findings confirm the hypothesis of the study, Fernandez says. Moreover, the results have clinical implications because if a patient presents with IHC 2+ disease, for example, they receive fluorescence in situ hybridization testing and will qualify to receive trastuzumab (Herceptin). Conversely, patients with IHC 1+ disease who are diagnosed with IHC 0 breast cancer won’t qualify for trastuzumab, which is not optimal, Fernandez concludes.