TP53 and plasma cell myeloma: Interestingly, butyrate and doxorubicin potentiated apoptosis of myeloma cell lines, irrespective of p53 mutational status, and reduced the viability of fresh myeloma cells from patients who had been relapsed on a variety of therapies including liposomal doxorubicin (patient samples P02, P08, P15 and P16, Supplementary Table 1).