PGR and breast cancer: We then mapped onto the BC atlas the publicly available50 single-cell transcriptional profiles obtained from five triple-negative breast cancer patients enrolled in a clinical trial for neoadjuvant chemotherapy treatment with a pathological evaluation of haematoxylin and eosin-stained tissue sections, immunohistochemistry analysis of oestrogen receptor (<1%) and progesterone receptor (<1%) and fluorescence in situ hybridization analysis of HER2 amplification (ratio of HER2 to CEP-17 < 2.2).