The emergence of new tumour lines during therapy.
D000970:Antineoplastic Agents / Q000009:adverse effects*; D003520:Cyclophosphamide / Q000009:adverse effects; D006801:Humans; D008558:Melphalan / Q000009:adverse effects; D009101:Multiple Myeloma / Q000188:drug therapy*; D009154:Mutation; D009378:Neoplasms, Multiple Primary / Q000139:chemically induced*
D000970:Antineoplastic Agents; D003520:Cyclophosphamide; D008558:Melphalan