APC and neoplasm: Consistent with this role for tankyrases in Wnt signaling regulation, small molecule inhibitors of tankyrase which impair PARylation activity by competing with β-NAD+ for tankyrase binding, reduce AXIN PARylation, stabilise the β-catenin destruction complex and thus inhibit Wnt signaling, even in tumour cells with APC mutations that otherwise have constitutive Wnt activity3.