Tyrosyl-DNA Phosphodiesterase 2(TDP2), belongs to the CCR4/nocturin family of divalent cation-dependent phosphodiesterases.TDP2 associates with CD40, tumor necrosis factor(TNF) receptor-75 and TNF receptor associated factors(TRAFs), and inhibits nuclear factor-kappa-B activation. TDP2 is characterized by similar sequence and structure as APE1 endonuclease, which participates in DNA repair and the activation of transcription factors.