However, since M89b has no anti-tumor activity in a PDAC–PDX without GAL2R expression (Figure 1E–H), it appeared that either M89b failed to translocate across the cellular and nuclear membranes to reach HDAC6 in tumor cells or the inhibition of HDAC6 by M89b in vivo was incapable of yielding an anti-tumor effect. Here, HDAC6 is linked to neoplasm.