In order to investigate if p53 protein isoform expression could provide independent information regarding sensitivity to differentiation therapy in AML patients, we performed a correlation analysis between p53 protein isoform expression and in vitro sensitivity to VPA in primary AML cells (PBMC with >95% AML blasts) (n = 21) (see Table 1 for patient characteristics). The gene discussed is TP53; the disease is acute myeloid leukemia.