“…This suggests that approaches to cancer therapy should be sought that do not involve cell kill; one such approach envisions the conversion of malignant cells through induced differentiation to benign forms with no proliferative potential. This approach assumes that malignancy is not an irreversible state, as has been demonstrated with a variety of tumour types, including teratocarcinomas (Pierce & Wallace, 1971;Brinster, 1974), neuroblastomas (Schubert et al, 1971;Prasad, 1983) squamous cell carcinomas (Pierce & Wallace, 1971), leukaemias (Metcalf et al, 1969;Paran et al, 1970;Gootwine et al, 1982), and adenocarcinomas of the breast (Decosse et al, 1973;Pierce et al, 1977). The use of differentiation as a therapeutic approach also presumes that cancer is a disease of altered maturation.…”