Abstract Ki67 immunohistochemistry (IHC), commonly used as a proliferation marker in
breast cancer, has limited value for treatment decisions due to questionable analytical …

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged
as a targetable subset of breast tumors, based on the evidence from clinical trials of novel …

Background Among breast cancers without human epidermal growth factor receptor 2
(HER2) amplification, overexpression, or both, a large proportion express low levels of …

Background The development of anti-HER2 antibody–drug conjugates opens new
therapeutic options for patients with breast cancer, including patients with low expression of …

Novel antibody-drug conjugates against HER2 are showing high activity in HER2-negative
breast cancer (BC) with low HER2 expression (ie, 1+ or 2+ and lack of ERBB2 amplification) …

Background Trastuzumab targets the extracellular domain of the HER2 protein. Adding
trastuzumab to chemotherapy for patients with early-stage, HER2-positive breast cancer …

Triple negative breast cancer (TNBC) continues to be the subtype of breast cancer with the
highest rates of recurrence and mortality. The lack of expression of targetable proteins such …

Importance Given conflicting results regarding the prognosis of erb-b2 receptor tyrosine
kinase 2 (ERBB2; formerly HER2 or HER2/neu)–low breast cancer, a large-scale, nationally …

Background HER2-low breast cancers were reported to have distinct clinicopathological
characteristics from HER2-zero; however, the difference in their genetic features remains …

Simple Summary The dichotomous classification of HER2 status is experiencing a paradigm
change, leading to the identification of the so-called “HER2-low” category. The aim of our …