-Importance of PR status--personally unsure if true for her2+s

[Lani]

her2+ breast cancer seems to have different pathways driving it and may not act the same way as "generic" breast cancer--that which comprises all breast cancers lumped together, most of which are her2- and skew the statistics/results:


Progesterone status provides important information in breast cancer

MedWire News: Women with breast cancer are more likely to respond well to adjuvant hormone therapy if their tumors express the estrogen and progesterone receptors (ER+/ PgR+), rather than the estrogen receptor alone (ER+/ PgR-), suggests a study.

Emad Rakha (University of Nottingham, UK) and colleagues also report that single hormone receptor positive tumors - ER+/PgR- or ER-/PgR+ - are "clinically and biologically distinct groups of breast cancer" that require different treatment strategies.

The team of researchers investigated 1944 women under the age of 70 years who presented with primary invasive breast carcinoma between 1986 and 1998. Information on clinical and biological characteristics was collected and women were monitored for a median of 9 years.

Noting that the significance of the single receptor-positive breast cancer phenotype is poorly understood, the researchers stratified patients according to ER and PgR expression.

In total, 272 (15.6%) women had tumors that were ER+/PgR-, 60 (3.4%) had tumors that were ER-/PgR+, while 963 and 448 women had double-positive (ER+/PgR+) and double-negative (ER-/PgR-) tumors, respectively.

Among 503 women receiving adjuvant hormone therapy, those with tumors that were ER+/PgR- had a 1.9-fold decrease in both overall survival and disease-free interval, compared with women with double-positive tumors.

Rakha et al comment in the Journal of Clinical Oncology: "We believe that assessment of PgR can provide important prognostic information and prediction of response to adjuvant hormone therapy in estrogen receptor positive tumors."

The researchers found that older, postmenopausal women tended to have ER+/PgR- tumors that were moderately differentiated.

In contrast, most of the ER-/PgR+ tumors occurred in younger, premenopausal women and were poorly differentiated. These tumors also tended to have biomarkers of poor prognosis such as positive expression of p53 and basal cytokeratins, and reduced E-cadherin expression.

This, say the researchers, shows that the single hormone receptor positive tumors are biologically distinct, with ER-/PgR+ tumors the most aggressive subtype.

"The differences observed suggest that consideration be given to exploring the behavioral characteristics of these tumors with respect to treatment response in more detail," they say.



J Clin Oncol 2007; Advance online publication

http://jco.ascopubs.org/

[Jean]

Thanks Lani,
Hopefully soon (dear God) we will be treated for the sub-type of bc
we have.

jean

[Becky]

Dear Lani

This is an important piece of research for a variety of reasons. First, the timeframe was between 1986 and 1998 - a time when Her2 was not being tested (herceptin was even being used on metastatic bc until the end of November, 1998). Second - with an age group of less than 70, they were capturing (most likely, postmenopausal women) and also, only Tamoxifen was available.

Since I am ER+ but PR neg, I try to find out as much as I can about this pathology because it is very, very rare (although ER neg, PR+ is rarer). You are right about your statement that it may not pertain to those who are Her2+ as well except for the fact that it further supports that Tamoxifen does not work well unless one is highly ER and PR positive and does not work well unless one is at least positive for both ER and PR.

In my research on ER+/PR neg (prior to all the knowledge about Her2 and the Her family in general), all papers point to the fact that these pathologies don't do well and that is because other factors are in play. Some older studies show that 58% of women who are ER+ but PR neg are also Her2+ (well that explains all of us on this board that are ER+ and PR neg like Jean and me) and if they are not Her2+ then another 30% tested positive for EGFR (aka Her1). The others can probably be explained by Her4 or IGFR - but basically, if you are lacking one or both hormone receptors, something else is driving your cancer too.

Thanks for the article as it reaffirms all the things they are finding about hormone negative or partially hormone negative bc.

[Hopeful]

I thought it would be interesting to review this thread from a few weeks ago http://her2support.org/vbulletin/sho...eferrerid=1173 in conjunction with the post that begins this current thread.

There do appear to be definite associations between Her2 and PR expression.

Hopeful

[saleboat]

http://www.breastcancerupdate.com/do...9;Regan_14.mp3

[Lani]

I usually try to listen to everyone on BCU, but I missed Dr. O'Reagan. Glad you corrected that!