ABCG2 and neoplasm: To test whether in the olaparib-resistant cohort there is a link between the increase in proportion of MSCC/EMT-like tumours and the up-regulation of the P-gp Abcb1a, Abcb1b and Abcg2 [3], we compared their expression in olaparib-naïve and olaparib-resistant tumours.