CD274 and triple-negative breast carcinoma: PD-L1 glycosylation antagonized its interaction with GSK3β, preventing GSK3β-mediated PD-L1 destabilization.491 In a study of triple-negative breast cancer, β-1,3-N-acetylglucosaminyltransferase (B3GNT3)-mediated PD-L1 glycosylation increased PD-L1 protein stability and PD-L1/PD-1 interaction.