In order to profile the substrates of RNF111, we have generated U2OS osteosarcoma CRISPR modified cell lines that express a truncated form of RNF111 devoid of the C-terminal RING domain (RNF111-RING-KO) that mimics the truncation observed in the cancer cell line NCI-H460. The gene discussed is RNF111; the disease is osteosarcoma.