19-Phenyl and 19-methyl DMAGwere validated as Hsp90 inhibitors in human breast cancer and humanneuroblastoma cell lines using the molecular signature of depletionof Hsp90 client proteins and the induction of alternative heat shockprotein chaperones, Hsp70 in breast cancer cells and both Hsp70 andHsp27 in neuroblastoma cells. Here, HSP90AA1 is linked to breast carcinoma.