The transformation of MSCs has been achieved under the controlled expression or deletion of certain genes, such as by the expression of the EWS‐FLI‐1 chimeric gene to induce Ewing sarcoma 10, the deletion of p53 to induce leiomyosarcoma 11, and the deletion of the retinoblastoma (Rb) gene to induce liposarcoma 12. The gene discussed is RB1; the disease is liposarcoma.