Need help understanding report

These letters stand for antibodies that were used to stain the slides (cells) to be sure the cells were breast carcinoma rather than benign or cells from another possible cancer like thyroid, lung, colon, etc.  The tests confirmed for the pathologist that the cells were from a recurrent IDC and not something else. The tests also confirmed that the BC cells were ER (estrogen receptor) positive, which tells your oncologist that it may still respond to an anti-hormonal treatment.  As to what the letters stand for CK7 (cytokeratin 7, a marker for breast cancer), BRST-2 ( also known as GCDFP-15, a marker for breast cancer), TTF-1 (thyroid transcription factor 1, a marker for thyroid and lung carcinoma), Pankeratin (a breast cancer marker), E-Cadherin (a marker for an adhesion molecule in breast cancer).  I don't know a lot about all this, so please have your doctor tell you more and answer your questions.  Good luck to your mother-in-law.  It's really unfortunate that she is dealing with this again, but it's nice that you can help her with this.