HER2-low breast cancers: Current insights and future directions

• Published in: Seminars in diagnostic pathology Vol. 39; no. 5; pp. 305 - 312
• Main Authors: Zhang, Huina, Karakas, Cansu, Tyburski, Haley, Turner, Bradley M, Peng, Yan, Wang, Xi, Katerji, Hani, Schiffhauer, Linda, Hicks, David G
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.09.2022
• Subjects: Biology; Breast cancer; HER2; HER2-low; Pathology; T-Dxd; Trastuzumab-deruxtecan; Pathology; HER2-low; T-Dxd; Trastuzumab-deruxtecan; Breast cancer; Biology; HER2
• ISSN: 0740-2570; 1930-1111
• DOI: 10.1053/j.semdp.2022.07.003

In light of the significant clinical benefits of novel HER2-targeting antibody-drug conjugates in advanced HER2-low expressing breast cancers in recent phases I and III clinical trials, particularly trastuzumab-deruxtecan (T-Dxd), the new “HER2-low” category in breast cancers (breast cancer with a HER2 IHC score of 1+, or 2+ without gene amplification) has gained increasing attention. In the past year, “HER2-low” breast cancers have been under active investigation by both oncologists and pathologists. In this current review, we update the recent cutting-edge research on HER2-low breast cancers, with a focus on the biology of HER2-low breast cancers, the issues on the identification of HER2-low breast cancers by immunohistochemistry in current practice of pathology, and the future directions in this emerging category in breast cancers.