Question: I recently had a breast biopsy with invasive ductal carcinoma, grade 3 and ductal carcinoma in situ. My report said “the carcinoma is estrogen and progesterone receptor negative (<5%) and negative for her2/neu over-expression (1+).” I read online that sometimes even less than 5% could still be positive for the estrogen receptor. Thank you for your help.

Answer: Yes it’s true that having fewer than 5% positive cells could still be considered positive for estrogen and progesterone receptors. Did your report give you a specific percentage or just <5%? Recent recommendations from the American Society of Clinical Oncology suggest staining of at least 1% of the tumor should be considered positive.  Whether or not your cancer is receptor positive or negative can have a significant impact on your treatment decisions. If the report doesn’t mention a specific percentage you could ask your doctor to have the pathologist look back at your slides and give a percentage.