CA125-negative populations were significantly higher in HGSCs not amenable to complete resection (sub-optimal cytoreduction) compared with tumours that could be totally removed on initial surgery (optimal cytoreduction) (29.4±10.0% (n=6) versus 16.8±6.7% (n=10), median±IQR; P=0.004 unpaired two-sided t-test; Fig. 1a and Supplementary Data 1). The gene discussed is MUC16; the disease is neoplasm.