Can herceptin/perjecta change HER status?

waterdog

My initial biopsy showed HER+++. I received neoadjuvent chemo which included herceptin and perjeta which I will continue on until March 2015.  My final pathology showed HER++ which, if I understand correctly, means that the tumor does not over express HER. My MO said he doesn't know what to make of that other than receiving herceptin and perjeta may modify the HER status of the tumor.  Anyone else?

ben50

I believe Her2++ is still considered positive, just not as positive as +++, if you will. When a tumor is ++, the benefit of targeted therapy becomes less clear but they still regularly administer Herceptin and Perjeta if they deem you will receive benefit . Because your final pathology indicated ++, maybe you were never +++ to begin with? Hard to know -- but it appears your cocktail is definitely having some effect!

SpecialK

ben50 is correct - Her2++ is a positive measure of Her2 expression, but only fairly recently has been considered positive enough to benefit from targeted therapy, generally offered only at the 2.0 (++) level, but not less than that. Was the same testing method used for both samples - biopsy and surgical?  Depending on the lab used, their testing method may differ.  Another possibility is that since tumors are not always homogenous - sampling different areas of the same tumor can yield differing degrees of hormonal receptor positivity/negativity and Her2 amplification.  I have linked some study info on this subject:

http://www.ncbi.nlm.nih.gov/pubmed/22388760