The identification of HER2-low and HER2-ultra low categories in breast cancer has significant implications for the broader classification and understanding of breast cancer subtypes. Traditionally, HER2-positive breast cancer has been a distinct subtype associated with aggressive behavior and targeted treatment with HER2-directed therapies like trastuzumab. However, the emergence of HER2-low and HER2-ultra low categories challenges this binary classification by introducing a spectrum of HER2 expression levels that may have therapeutic implications.
These new categories suggest that HER2 expression exists on a continuum rather than a dichotomous classification. This challenges the traditional view of HER2 as a binary marker and raises questions about the heterogeneity within HER2-negative tumors. It also highlights the complexity of HER2 signaling in breast cancer and the potential for different levels of HER2 expression to impact treatment response.
Furthermore, the identification of HER2-low and HER2-ultra low categories may lead to a reevaluation of treatment strategies and the development of novel therapies targeting these specific subgroups. Understanding the biology and clinical behavior of these subtypes could pave the way for personalized treatment approaches tailored to the level of HER2 expression in individual patients.