Tuesday, June 28, 2016

That Er+/Pr+ Thing

So I haven always known (well since my diagnosis - before my diagnosis what I knew about breast cancer wouldn't fill a post-it) that have a hormone receptor positive breast cancer had a lot of impact on your treatment protocol. But I didn't know that much about how that worked.

Now I am learning more. In the past, estrogen was considered to be the indicator of breast cancer diagnosis. When estrogen was detector at a biopsy, it was considered an indicator of breast cancer. Now it has been determined that progesterone has a big impact as well.

"Previous studies have demonstrated that estrogen receptors react to the primary female sex hormone, estradiol, by activating genes that nudge cancer cells into growing and replicating. The cells divide faster and live longer, which results in a more advanced state, Greene explained.

The study concluded that when progesterone or progestin is added, an entirely new set of binding sites opens up, allowing the estrogen receptor to work in conjunction with progesterone receptors. The process stops cell reproduction and survival and "our data further suggests that, despite the historical bias toward the effects of estrogen on the estrogen receptor," Greene said. "It’s the progesterone receptor that dominantly controls estrogen activity when both receptors are present and activated.""

Well whoop de doo. This sounds all kinds of complicated. But I think its important.

"During the study, Greene and his colleague Haral Singhal inhibited the activity of both estrogen and progesterone receptors in three groups of mice by treating them with either the estrogen receptor antagonist tamoxifen, an experimental progesterone receptor antagonist called CDB4124, or a placebo. Predictably, tumors in untreated mice grew quickly. Tamoxifen halted tumor growth, but did not shrink them, while CDB4124 had a more complicated effect: It caused the tumors to shrink at first, but after 35 days, they began growing again and ended up 50 percent larger than their original size. A combination of the two antagonists seemed to be the golden ticket: tumors showed “virtually full regression,” according to Singhal.

“These findings,” the study reads, “emphasize the clinical value of assessing both progesterone receptor and estrogen receptor expression in breast cancer samples.”"

Sorry its a bit technical but this is a big change in looking at breast cancer treatment options.

1 comment:

Becky said...

Hi Caroline,
Can you tell me where you found the study information? I had three primary tumors, a grade 1, 2, and 3. They were all 95% ER+ but what different was the PR levels - and the higher the PR the higher the tumor grade. So exactly what they are saying about how the PR level affects the speed of tumor growth and it has always bothered me that the focus has been on reducing estrogen in my body but nothing is being done to block progesterone ... but I also don't understand the biology of it all (like how the body creates progesterone and does that only happen when it has estrogen?) Anyways, I'd like to see the actual study and might even ask my oncologist about it.

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