Furthermore, in human colon cancer cells, Etsuko Shibata et al. reported that cells lacking detectable ORC1, ORC2 or ORC5 still grow, recruit MCM2-7 and initiates DNA replication; this implied that ORC1 or ORC2 or ORC5 seems dispensable to DNA replication 22. Here, ORC1 is linked to malignant colon neoplasm.