Conclusion: Compound 23 modulates the PI3K/HDAC pathway, which results in significant inhibition of hematologic tumor proliferation in vivo and in vitro. The differential levels of ERBB2 and ERBB3 might be related to the difference in the effect of compound 23 on hematologic tumors and solid tumors. Here, HDAC9 is linked to hematopoietic and lymphoid cell neoplasm.