Some cancers, including breast, can make HER2 in higher-than-normal amounts.
What Does HER2-Low Mean?
HER2-low describes a breast cancer subtype “in between” HER2-positive and HER2-negative.
The cancer cells have some HER2 protein on their surfaces but not enough to be considered HER2-positive.
Besides HER2 status, several other factors are considered when devising a personalized breast cancer treatment plan.
The main distinction among the HER2 subtypes is that HER2-positive breast cancers tend to be the most aggressive.
HER2-positive breast cancers are also more likely to recur.
What Is Immunohistochemistry?
Immunohistochemistry(IHC)is the first laboratory test performed to identify HER2 status.
HER2-low breast cancer was previously classified and treated as HER2-negative breast cancer.
No targeted therapies were available until 2022.
In this case, the monoclonal antibody istrastuzumab, and the chemo drug is deruxtecan.
When inside the cell, the deruxtecan part of Enhertu is released, causingDNAdamage and cell death.
Is HER2 Low Good or Bad?
Breast cancer treatment is complex and requires a personalized approach.
All said, HER2 is certainly a vitalprognostic(measure of outcome) marker in breast cancer.
Regarding HER2-low breast cancer, experts are still learning more about this subtype.
However, the fact that cancer responds to HER2-targeted therapies, like Enhertu, is promising.
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National Cancer Institute.Enhertu improves survival for metastatic HER2-low breast cancer.
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American Cancer Society.Breast cancer signs and symptoms.
DeSantis CE, Ma J, Gaudet MM, et al.Breast cancer statistics, 2019.CA Cancer J Clin.
2022;387(1):9-20. doi:10.1056/NEJMoa2203690
