CASE: 54yo post-menopausal 👩 with HR+/HER2- (IHC 1+, 🐠FISH neg) MBC who had disease progression on 3 lines of endocrine/targeted rx, then capecitabine.
What is HER2-low #BreastCancer?
🔹 HER2 IHC 1+ or 2+/ISH neg
🔹 Large % of HR+ BC (~67%), less in TNBC
🔹 Prognosis/biology indistinct from HER2-0
🔹 Unreliable IHC scoring; need better tests!
🔹 NOT a BC subtype; but targetable
A thread 🧵...
When I was a med student, I loved internal medicine but I couldn’t find a resource to help clearly organize the vast amount of information… so I started taking my own notes. I added to them throughout residency and they became my external brain: everything I knew about IM!