Low HR positive breast cancer

Expert: Giancarlo Pruneri, National Cancer Institute - IRCCS Foundation, Milan, Italy Questions:  1-Can You explain what is meant by the title „low positive“ luminal breast cancer?  2-Is that treshold (<10%) uniform everywhere, in the entire oncology /pathology/ community? 3-What are the guidelines to follow on this question?  4-Can You comment on the two tresholds for defining positive HR status (≥1% vs ≥10%)?  5-Is there an implication on therapeutic approach (i.e. how should we be treating these cases, should they receive ET)? Please explain.