CCNE1 and neoplasm: To determine the impact on tumour growth in vivo, we established tumours from HR-proficient OVCAR3 cells harbouring amplified CCNE1, which confers primary treatment resistance and poor outcome of HGSC.8 We assessed tumour growth (Fig. 5b) and survival (Fig. 5c) in response to treatment with CX-5461 (30 mg/kg), topotecan (5 mg/kg) or CX-5461 plus topotecan.