SelSA is an orally active, selective inhibitor of histone deacetylase 6 (HDAC6) with an IC50 of 56.9 nM. It inhibits the phosphorylation of ERK1/2 and suppresses the proliferation of breast and liver cancer cells, with IC50 values ranging from 0.58 to 2.6 μM. Additionally, SelSA inhibits migration and invasion of Huh7 cells and induces apoptosis. This compound also demonstrates antitumor activity in mouse models.