Is HER2-Zero Real?

If you stare hard enough, you’ll see pink. That’s the hypothesis as the oncologists debate whether true HER2-null disease exists or whether today’s analogue IHC simply misses a scarce receptor population. They float a future of AI-quantified H-scores, acknowledging that heterogeneity means one field can hide 1 % staining while another screams zero. Until digital pathology catches up, they still require some immunohistochemistry to justify T-DXd, but concede the binary lexicon is living on its death bed.