(+)-JQ1 is a BET bromodomain inhibitor, with IC50 of 77 nM/33 nM for BRD4(1/2) in cell-free assays, binding to all bromodomains of the BET family, but not to bromodomains outside the BET family. (+)-JQ1 suppresses cell proliferation via inducing autophagy. (+)-JQ1 inhibits the expression of Nuclear receptor binding SET domain protein 3 (NSD3) target genes.