This is a Medscape article, and may require registration (free) to access:
http://www.medscape.com/viewarticle/575746
Of particular interest:
"Among the 34 regional/distant relapses:
- 11 changed from ER/PR positive to ER/PR negative
- 14 changed from ER/PR negative to ER/PR positive
- 3 changed from HER2 negative to HER2 positive
- 6 changed from HER2 positive to HER2 negative."
Hopeful