HER2 Mutant - Is There a Receptor on the Cell Surface?

The traditional understanding is the one on the left hand panel. You had lots of HER2 protein on the cell surface, you just need a lot more for the drug to bind and therefore get it. That's the traditional dogma. And in a way, without having too much HER2 protein they kind of just go into the hyperactive where they internalize into the cell and then it gets recycled. So that, if you attach an antibody drug conjugate onto it, it literally just sucks the drug into the cell.