HER2- BC may have HER+ mets

[al from Canada]

Here's a real scarey situation for women with HER- primary tumors with mets.:

HER-2 overexpression, a predictive marker of tumour aggressiveness and responsiveness to therapy, occurs in 20-30% of breast cancer. Although breast cancer is a heterogeneous disease, HER-2 measurement is carried out in primary tumour. This study aims to evaluate HER-2 overexpression in primary and metastases and its effect on treatment decisions. Biopsies from primary breast cancer and corresponding metastases from 58 patients were studied. HER-2 overexpression was evaluated immunohistochemically in all primary and metastatic sites. Positive overexpression in primary and/or metastases was confirmed by fluorescence in situ hybridisation (FISH). Discordance in HER-2 overexpression between primary and metastatic sites was 14% (eight of 58 patients). Concordance was found in 50 (86%) of patients (95% CI: 77-95). In one patient (2%), HER-2 was negative in metastasis but positive in primary. In seven (12%) patients, HER-2 was positive in metastases and negative in primary (95% CI: 3.7-20), and three of them responded to trastuzumab. Gene amplification by FISH was found in all cases with HER-2 positive (+2 and +3) by immunohistochemistry. Our data suggest that a possible discordance of HER-2 overexpression between primary and metastases should be considered when making treatment decisions in patients with primary HER-2-negative tumours.

Sounds like all mets should be biopsied and tested for HER2

May be good advice for Oncs.

Al

[AlaskaAngel]

Fighting cancer is not a lot different from trying to avoid being a war casualty, keeping ears and eyes out for the best information and then using it strategically. With the Human Genome Project, the amount of scientific information has exploded and it is very hard for doctors to keep up with even just theorizing, much less any clinical trial results and then how to best use them. If your source is trustworthy, your suggestion makes very good sense even though unfortunately it takes too much time to conduct long enough clinical trials to convince medical providers to deal with information like this. Thanks, Al.

A.A.

[Unregistered]

I have seen other documentation making the same observation.

I will post it if I can find it.


RB

[cath_ob]

Please keep replying as you discover more information.
thanks
Cathy

[MichelleMoon]

Thanks for sharing, Al.

My HER2 status did a flip upon mets! My primary BC tumor did not overexpress HER2neu, but my lung mets were slightly HER2+ by FISH.

Just reemphasizes the fact that mets needs to be tested for ER/HER2.

[Sheila]

I am wondering how many of those that were diagnosed as Her2 - originally were done by IHC and not FISH, and possibly were not accurate....and were actually Her2 +. There was alot of discussion at the SABCS on diagnostics of tumors, and slides, grinding up the tumor versus section slides, and basically your diagnosis is reflective on the quality of pathology lab that performs it.

[Jean]

Isn't it also true that hormonal status can change from the primary tumor
if disease has metastasize?

Jean