In another study, salivary actin cytoplasmic 2, Ig γ-1 chain C region, S100-A8, and S100-A9 were upregulated and selected through proteomic analysis, and S100A8/A9 levels were increased in parotid saliva (n = 83), but not in whole saliva (n = 56) of patients with SS compared to those of HCs and those with non-SS dry mouth disease [59]. Here, S100A9 is linked to synovial sarcoma.