Patients with IHC "weak" scores and FISH "strong" scores

[Barbara2]

IHC measures the receptors on the outside of the cell. A 2+ or 3+ reading on IHC are considered Her2 positive. However, I've read that in the past, 2+ patients were considered harder to treat because they kind of "fall between the cracks" in what type of treatment needed. (Although today, they would get Herceptin..)

FISH measures the copies of the Her2 gene inside the cell.

I am IHC 2+ and FISH 8.6 (high score). I'm wondering if the IHC "weak" people don't do as well on herceptin, because herceptin targets HER2 receptors outside of the cell and these people have fewer receptors there.

Maybe these IHC somewhat "weak" people but "strong" in FISH, would do better when treated with agents that target the inside of the cell, such as Lapatinib.

But the Lapatinib trials will only take you if you are stage 3 or metestatic. My tumor was 1/4 of a centimeter from meeting the classification of stage 3. And thankfully, still NED. I'm currently getting late herceptin, but after reading how some drugs target Her2+ from the outside of the cell, and some from the inside, it has me wondering......

Does anyone know of anything other than Lapatinib that targets HER2+ from the inside of the cell? (That's a big question, I know.........)

Barbara2

[saleboat]

Hi Barbara,

The cancer that I had was IHC negative, and FSH positive. There is no difference in Herceptin response rates given this profile. I found the attached helpful:
http://www.labcorp.com/clinicaltrials/what/HER2.pdf

Also, I believe that an IHC score of 2+ is only considered appropriate for Herceptin when the FSH is positive. In my case, if I were IHC 2+ and FSH negative, I would not be considered a candidate for Herceptin.

Jen

[Barbara2]

Thank you for posting. The article was interesting, but old. February 2002. Maybe by now there is more insite regarding IHC and FISH tests; how to use the results in treatment, targeting the inside vs outside of HER2+ cells, etc.
Thanks, again.

[Lolly]

Barbara, Lapatinib (Tykerb) is what's known as a tyrosine kinase inhibitor; there's another one in trials now called Tarceva. I posted a link on a Phase II trial of Tarceva on the clinical trials page just now. However, the criteria specifies MBC patients. But you might want to look at it anyway as the study details are interesting and perhaps later trials will include earlier stage volunteers. Worth checking out.

<3 Lolly

[Leslie S]

Hi,
I agree with Jen. I was tested initally by IHC as a 2+. In our area, those in that itermediate zone are retested by FISH. I came out FISH negative, so Herceptin was not indicated.
Leslie

[Johanna Johannsdottir]

Hello,


I was tested first with IHC that didn't give absolut result. Tested again in FISH that gave HER++ result and now on Taxotere/Herceptin. Im told this is the normal procedure here in Iceland, first IHC and if not absolut then FISH.

regards.
Jóhanna

[sadie]

This site has some interesting info on IHC 2+ & Fish 3+ testing.

Also has interesting info on Herceptin results.
Sadie
http://clinicaloptions.com/layouts/C...2-E964EA6098A0}

[Barbara2]

Thank you to all for your replies. They were most helpful.

Barbara