[Lani]

not only may your tumors be different than tumors in any other her2+ breast cancer cases, but each of your tumors/mets may be different from each other.

Each time the tumor mutates, either in response to a new treatment or to a change in the microenvironment or whatever else the new tumor may seed another area, or it may mutate after it is "planted" or it may be this met was from one of a large number of heterogenous clones in the original tumor or it may be that the breast cancer stem cell/progenitor cell of that met differentiated differently from another.

This is why mets when biopsied often end up having different hormone and her2 receptor status than the primary.

Makes it hard to fight your enemy when it is constantly changing...a reason to get biopsies of mets whenever possible--so you know what you are fighting!

Also a reason to use multiple modalities in the fight--surgery, focused ultrasound, various ablation procedures for the liver, perhaps radioactive iodine if met has Na-I symporter receptors on it(search my previous posts for Irene Wapnir, MD who may be doing this study), intrathecal therapies etc

Sorry to make this so complicated--but it IS complicated, that is the problem!

Glad the armory has a variety of ammunition!