FKBPL and breast cancer: A significant reduction in tumoursphere-forming efficiency (TFE) of 20–30% was obtained across all cell lines, PE01, PE04, OVCAR3 and OVCAR4 cell lines (Fig. 1a–d), similar to what we had observed in breast cancer cell lines with the preclinical peptide, AD-01.23 FKBPL levels were assessed in all cell lines, with highest expression observed in OVCAR4 cells and lowest expression in PE01 cells (Fig. 1e).