Can HER2 status change from Positive to Negative?

Keena208

Hello, ladies.

I started neoadjuvant treatment (taxol x12, ACx4) in April. At this time I was diagnosed HER2 positive. After 8 rounds of taxol and 5 herceptin, my oncologist recommended that I had mastectomy because he thought there was some dead tissue around the tumor.

I just got the pathology report back. Looked like my tumor was reduced in size significantly and only 1 node came back positive.

What is bothering me now is that it shows HER2 as Negative (+1)!!! Has anything like this happened to you or has anybody heard about HER2 status changing from Positive to Negative? I have such high hope for herceptin. Can this be true? Why is this happening?

Any info would be appreciated!!

kerri72

Maybe the neoadjuvant Herceptin killed off most of the Her2+ cancer cells, so at the time of surgery what was left of your tumor wasn't as strongly Her2+? Hopefully someone here will be able to answer you definitively, but that seems like a possibility. Your onc should have an answer too.

Hindsfeet

Study finds HER2 status can change between primary and metastatic breast cancer

http://www.knowbreastcancer.org/news-research/news/her2-protein-and-gene.html

HER2 status changes

Several studies have reported that HER2 status can differ between a primary tumor and its lymph node metastases (known as discordance) and that the status can continue to change during disease progression. In other words, a woman with an HER2+ breast tumor can have HER2- lymph node metastases and vice versa. This happens in approximately 15% of cases. The possibility of discordance indicates a need to take biopsies and assess HER2 and hormone receptor status during disease progression in order to optimize treatment decisions.

One study found that HER2 expression can vary within an initial primary tumor and that this predicts shorter disease-free survival than consistent HER2 gene amplification. This appears to be more common when the biopsy results indicate low-grade HER2 amplification or questionable HER2 expression. Such findings indicate a need for HER2 testing on larger tumor samples for accurate assessment of HER2 status, according to the authors.

http://foodforbreastcancer.com/articles/latest-research-concerning-her2-positive-breast-cancer-prognosis

I guess it could happen as well in the primary tumor...like Kerri said, maybe Herceptin kills cells with the over expressed Her2+++ cells leaving behind Her2- cancer cells. That's encouraging that in just a few months the Herceptin worked.

seamstress

Two years after my original diagnosis (HER2+) I had mets to the spine and they were no longer HER2+.

Keena208

Hmm, I think mets are unlikely since I had to do some PET scan to participate in a clinical trial very recently.



A friend of mine had her doc told her that sometimes it depends on where the sample was taken from the tumor.



Who knows! I cannot wait to see my onc on Mon!!!!



Thank you!!!