YY1 and hepatocellular carcinoma: Our data (Shi, et al. Kynurenine derivative 3-HAA is an agonist ligand for transcript factor YY1) showed 3-hydroxyanthranilic acid (3-HAA), a structural analog of kynurenine, was selectively downregulated in HCC cells and exogenous 3-HAA promoted apoptosis in HCC in vitro and in vivo via binding with transcription factor YY1.