To investigate how inhibition of CRL4 E3 ubiquitin ligase activity inhibits ovarian cancer cell proliferation through CFP1, we used the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system to knockout CFP1 in ES-2 and A2780 cells (Fig. 2A). The gene discussed is CXXC1; the disease is ovarian carcinoma.