CA125-negative HGSC cells had a 670-fold greater tumour-initiating frequency than matched CA125 positive counterparts (1/1,100 versus 1/740,000 cells; median, n=7 per group; Supplementary Table 2), and in five of the seven HGSCs 100–1,000 CA125-negative cells initiated tumours (Fig. 2a, Supplementary Data 1 and Supplementary Fig. 3a). The gene discussed is MUC16; the disease is neoplasm.