Suggest Treatment For Breast Cancer

My aunt has recently been diagnosed with Brest cancer. I am a nurse but not practicing at the moment..but i couldnt answer her question cause i didn t know it the answer.. She said to me that her Dr is waiting on a test result that will decide which chemo she will have to get... She said it was something like. The 3 n s??? Two test to be negative and one positive and that decides which therapy for her. Is there anyway u can answer this for me so I can ease her worry... Or what s the name and what does it do , a test name similar to this description