To investigate if levels of different heat shock proteins could affect sensitivity to nutlin-3, intracellular protein levels of Hsp27 (phospho-Ser82), Hsp27 (phospho-Ser15), Hsp40, Hsp60, Hsp70 and Hsp90α were quantified in primary AML cells (n = 40) using an Hsp/Chaperone 8-plex MultiBead kit and flow cytometric analysis, while sensitivity to nutlin-3 was determined in 3H-thymidine incorporation assay (Figure 4A) (for AML patient characteristics, see Additional file 3). This evidence concerns the gene HSP90AA1 and acute myeloid leukemia.