However, compared to NTC controls the lower levels of SEPHS2 and GPX4 expression observed pre-implantation (Fig. 6E) were restored in sgSEPHS2 or sgSEPSECS tumours at endpoint (Fig. EV4D,E), suggesting that the counterselection of the interfered cells did not cause a tumour growth delay appreciable with the experimental settings employed. The gene discussed is GPX4; the disease is neoplasm.