PGR and breast cancer: For screening purposes, the experiments were repeated twice and generated dose–response curves in seven ERα-positive BC cell lines that represent diverse clinical surrogates, histological types, and variations in PR and HER2 expression (MCF-7, ZR-75-1, T47D-1, HCC1928, BT-474, MDA-MB-361, and EFM192C cells) (Table 1)21,22.