KNG1 and neoplasm: In a recent study, Appiah et al.73 attached BK to an acid-responsive N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer to create a polymer-BK conjugate, designated P-BK, which not only substantially extends the half-life of BK in the systemic circulation, but also enables acid-triggered release and activation of BK in the tumor milieu.