After confirming the knockdown efficiency of our short interfering RNA-mediated HDAC-1 and HDAC-7 silencing in the PANC-1 and MiaPaCa-2 cells (Fig. 6A), consistent with data presented above, we demonstrated that the siHDAC-1 and siHDAC-7 infected PDAC cells significantly lost their ability to formed tumor spheres (Fig. 6B). This evidence concerns the gene HDAC1 and neoplasm.