Comparison of clinicopathologic phenotypes of HER2-low versus HER2-negative and HER2-positive breast cancers

Breast cancer subtypes, distinguished by HR and HER status, have different clinicopathologic features. With recognition of the clinical relevance of HER2-low, there is debate as to whether this is a distinct subtype. Retrospective analysis of a prospectively maintained database at Memorial Sloan Kettering Cancer Center (New York, NY) compared clinicopathologic features of breast cancers according to HER2 status. The analysis found that clinicopathologic features of HER2-low tumors were primarily related to HR status. The authors conclude that these results do not support the characterization of HER2 low as a separate subtype.