Endocrine Response Enhanced in ER+/PR+ Tumors

[Hopeful]

AlaskaAngel,

It was surprising to see PR be a more important prognostic indicator than Her2. I agree, this is a stunningly overlooked factor for research.

Hopeful

[Becky]

So, do you think this is why Her2 positive cancers that are also ER/PR negative are more aggressive than those that are hormone positive?


I am always looking for information in regard to ER+ but PR neg bc because it is not very common and it is my pathology (as well as being Her2+).

From my investigations (and there is limited info out there), any work done on ER+ but PR neg usually also has a Her2 negative status as well. If the Her2 status is positive, this is looked upon as at least a known result (as researchers feel that the downregulation of PR is directly related to the upregulation of the Her pathway). So... if they find that an ER+ PR- tumor is also Her2+, they have an answer (as many of the Her2+ ones of this pathology tend to have a lesser (not a nonexistant) chance of also being Her1+ as well). However, if an ER+PR- tumor is also Her2 neg, it stands a GREAT chance of being Her1+ (and there's no "Herceptin" type drug for that except there are Her1 drugs out there).

Also, if ER+(but PR-) and Her2+, it has been shown that Herceptin and an aromatase inhibitor work very, very well together, better than if also PR+. The 2 researchers I spoke to at ASCO (who investigated this pathology), said that with adjuvant Herceptin in combination with an AI, it is really a triple punch for this pathology.

Any thoughts out there?

Kind regards

Becky

[Hopeful]

Becky,

I have done a lot of reading on the effect of PR status combined with Her2 status, and the conclusion I have seen drawn many times is that the ER+/PR- Her2+ pheonotype is more aggressive than PR+/ER- (rare, but it occurs) and ER+/PR+ Her2+ bc. I have copies of these articles but not where I am writing from at the moment and dashed if I can find the references when I want them. I will go through my other files and pull them for you if you are interested.

From your post, I gather you have read some of the research on PR- and Tamoxifen resistance, which is not the research I am referring to, but has a lot of info about the effects of ER+/PR- and Her2+.
I can provide a link to a recent abstract that concludes that ER+PR- breast cancer is growth factor dependent and constitutes a unique subgroup of ER+ patients which may be more likely to benefit from EGFR inhibition: http://meeting.jco.org/cgi/content/a...4/18_suppl/514; are the authors any of the people you spoke to at ASCO?

I would also like to thank you for the insightful comments you always provide and the terrific gift you have for translating complex techinical information into language that a lay person can understand.

Hopeful

[Becky]

A few of these names are ones I recognize but have to check when I get home. I do know all about PR- and tamoxifen resistance (and this was instrumental in deciding to get my ovaries removed to use Arimidex. The Herceptin/Arimidex combo data helped me convince my onc to give me 5 extra (every 3 week) Herceptin treatments so I could be on the combination one year (hence about 16 months of Herceptin versus one year). Everyone I have ever talked to about the ER+/PR- pathology say it is worse if you are not Her2+ as well. Data indicates that ER+/PR-/Her2- strongly indicateds Her1+ (aka EGFR) whereas with Her2+ it may well not be Her1+ as well. All have indicated that it is better for either hormone receptor to be positive rather than both be negative (as it is a pathway that has treatment options).


Thanks for your kind words and knowledge.

Becky