In what circumstances would you repeat bio markers (ER, PR, HER2) in a patient with breast cancer who has residual disease after neo-adjuvant chemotherapy?  

We typically do not repeat biomarkers in patients with residual disease after neoadjuvant chemotherapy as there are not clear guidelines or supportive data on how to use this information for treatment decisions. Treatment recommendations are based on initial biopsy results as long as the specimen i...

If there is any residual invasive disease after neoadjuvant therapy, I always repeat biomarkers. One of the biggest weaknesses of breast oncology is that we rely solely on pretreatment biomarkers in baseline tissue biopsy. This disregards tumor dynamicity and interaction with therapy, and will miss...