MLKL and synovial sarcoma: In SGECs of SS patients, the expression of apoptosis-related protein caspase-8 and necroptosis markers p-MLKL and RIPK3 is also upregulated (100); in NSG mouse models transplanted with PBMCs from SS patients, submandibular glands exhibited upregulation of Type I IFN and genes related to PANoptosis (necroptosis and apoptosis) (55, 101).