Weak Positive
 

This is my first post here. I tested HER2+ by FISH with a result of 2.1. I did not have an IHC test. I thought a weak positive was a good thing, but now I'm hearing that it means that the benefit I will receive from Herceptin is minimal. Is that true? If so, are the recurrence stats of someone weakly HER2+ the same as someone with a higher result?

I'd appreciate any information you might provide.

Thanks,
Pam

Hi Pam,
The weak/strong Her2/neu status refers to how much the Her2 factor is overexpressed in the tumor - in effect, how many copies of the receptor are on each cell. Her2 is a growth factor, which causes cells to divide and grow rapidly, which is why historically Her2 positive cancer has been associated with poor prognosis. The more Her2, the faster the cancer grows and the more likely it will recur. Strong Her2 positive cancer is more likely to respond to Herceptin because it has more of the targeted factor.
Having weak Her2 positivity doesn't necessarily mean you would not benefit from Herceptin, but it is true that you might not get as much benefit as someone with strong positivity.
On the other hand, weak Her2 positivity also means less rapid growth, possibly less aggressive disease which is a good thing!
It sounds like you're getting as much information as you can - keep it up, knowledge is power. Trust yourself that you will make the right decisions for you.
I wish you good luck in your journey- you'll find you are stronger than you think!
Chris

Chris, I'm trying to login and it won't let me, so it's still me (Pam). On Herceptin's website, it says that the benefits for Herceptin were greatest in patients who tested +++ by IHC and patients who tested FISH+ (with no number distinction). I tested FISH+. Can you tell me where you learned that the FISH result plays a part in overall benefit of the drug?

Thanks, Chris!

Pam

Hi Chris and Pam,

I've done quite a lot of digging on this subject, and I have never seen anything that correlates the strength of one's Her2+ score to one's response to Herceptin. In other words, if you're positive, whether you're IHC 3+ and FISH neg. (like me), you have the same chance of responding to Herceptin as someone who is IHC 2+ and FISH positive. I know that pathology reports usually report a score with one's FISH result, but I've never seen anything that relates that score to Herceptin response. (If that were true, I would never have received Herceptin being FISH neg...)

Jen

Hi,
Sorry if my response was confusing! I did not mean to imply that a person's score would correlate to the degree of response, just that strong positive is an indicator of who is more likely to respond to herceptin. This article is old (in terms of Her2 research, anyway!) but does explain a little bit about how the FISH and IHC are used. It basically says that by IHC, 3+ (strong positive) is a good indicator, but for IHC scores below that, FISH is a more accurate predictor. And it is true (according to this data) that FISH positive, no matter to what degree, seems to be a good indicator for responding to herceptin.
Bottom line is, just as with any treatment, the disease either will or will not respond - and the only certain way to determine this is with hindsight!

Pam, you didn't indicate ER/PR status. Are hormonals an option for you?


http://www.breastcancer.org/research...in_050001.html