PSIP1 and neoplasm: SUMOylation9 of LEDGF/p75 regulates its binding of promotor regions of stress-related proteins, enhancing the activation of AKT-signaling and resulting in increased tumor aggressiveness.9,10 Although it is known that LEDGF/p75 is involved in the DNA damage response and promotes signaling pathways of proliferation, chemoresistance and migration,11 the mechanistic background has not yet been conclusively clarified.