GATA-3 is almost exclusively expressed in ER+ patients and is also associated with lower tumor grade, older age at diagnosis, and the absence of Her2 over expression.
Here is a quote from a research study that I found: "GATA-3 is a transcription factor involved in human growth and differentiation. Gene expression profiling has shown that GATA-3 is highly expressed in the Luminal A subtype of breast cancer. A recent study found GATA-3 to be associated with favorable breast cancer pathologic features, including negative lymph node and positive estrogen receptor (ER) status. GATA-3 levels were also found to be an independent prognostic marker, with low expression predicting for breast cancer recurrence."
Yes, they need to take the lump out and further test it to see exactly what is going on. But from what I've read it is to be view in a more positive light then being negative in the other 3 markers (ER, PR, Her2) which is called triple negative bc. So don't panic and wait for the general surgeon to do his thing and then for the lab to do their thing so you oncologist will know exactly what is going on. There is absolutely NO NEED to rush into any thing. Believe it or not 99.9% of bc is slooooowwww growing. Most of us have bc growing inside of us for 6 to 8 years (on average) before it can be found as a tiny tiny lump or found on any type of x-ray.
Let us know when the surgery is and then how well you did with it. Hang in there.
take GOoD care