ORC1 and cancer: A few human cancer cell lines have been created by CRISPR-Cas9 mediated genome engineering where ORC1, ORC2, and ORC5 cannot be detected by regular immunoblots and yet the cell lines survive, proliferate and replicate DNA with the normal complement of origins of replication (Shibata et al., 2016; Shibata and Dutta, 2020).