Comparative studies using compound 24c, theHDAC3/8 dual degrader compound 24b, and the HDAC3-selectivedegrader compound 24a revealed that combined HDAC8 andHDAC3 degradation synergistically enhances breast cancer cell death,whereas HDAC8 degradation alone does not affect their proliferation. Interestingly, HDAC8 degradation alone effectivelysuppressed the growth of diffuse large B-cell lymphoma (DLBCL) cells,with significantly greater potency than the widely used HDAC8 inhibitorPCI-34051. Here, HDAC8 is linked to breast cancer.