Recently, changes in the stratification of ER positivity have been put forward by ASCO/CAP through an update of the recommendations for ER and PR determination, with the formal introduction of the ER-low-positive (ER-LP, defined as 1–10% of nuclear positivity in the tumour) [6]; this category has been known for some time to share more similarities with basal-type triple-negative breast cancer than with the luminal group [7–10], in morphological aspects, molecular signature and clinical behaviour. The gene discussed is PGR; the disease is neoplasm.