HER2 Support Group Forums - View Single Post - possible explanation of why some her+breast cancers are er+ but pr- and what it means

Lani · 09-29-2006, 08:37 PM

there was one by Arpino showing that in general ER+PR- tumors are resistant to tamoxifen, but sensitive to AIs(no mention of her2 though, if I remember)

'Becky--I am just starting to form an idea of what this might be implying.Unfortunately, neither the North American Trials nor the HERA trials divided out the her2+ER+ patients with respect to PR+ or PR- in the results I have seen.

I am still curious as to what implications this has with respect to the stem cell theory of breast cancer. Is her2 on those cells, is ER+ or PR+ or all all three receptors only present on progenitor cells? Also, are there different gene expression profiles, prognoses and different responses to therapy and natural history (eg time to recurrence) between her2+ er+pr-s and triple positives.

I am still reading and truly haven't formed an opinion yet.

As always I seem to have raised more questions than answers.

Was without internet access for 3 days, so way behind on reading enough to let me formulate an educated opinion yet. It is now 5am here --tried to make up for the 3 days out of touch and got carried away. Sorry I'm not much help for the moment!

09-29-2006, 08:37 PM	#5
Lani Senior Member Join Date: Mar 2006 Posts: 4,778	Hopeful, beside your article,,, there was one by Arpino showing that in general ER+PR- tumors are resistant to tamoxifen, but sensitive to AIs(no mention of her2 though, if I remember) 'Becky--I am just starting to form an idea of what this might be implying.Unfortunately, neither the North American Trials nor the HERA trials divided out the her2+ER+ patients with respect to PR+ or PR- in the results I have seen. I am still curious as to what implications this has with respect to the stem cell theory of breast cancer. Is her2 on those cells, is ER+ or PR+ or all all three receptors only present on progenitor cells? Also, are there different gene expression profiles, prognoses and different responses to therapy and natural history (eg time to recurrence) between her2+ er+pr-s and triple positives. I am still reading and truly haven't formed an opinion yet. As always I seem to have raised more questions than answers. Was without internet access for 3 days, so way behind on reading enough to let me formulate an educated opinion yet. It is now 5am here --tried to make up for the 3 days out of touch and got carried away. Sorry I'm not much help for the moment!