In a proteomic study, human kallikreins 1, 6 and 11 have been found to have significantly different abundances in the saliva of SS patients, with KLK6 and KLK11 being upregulated in all patient groups vs healthy subjects, and KLK1 being downregulated in patients with high focus score and upregulated in patients with low focus score (54). This evidence concerns the gene KLK6 and synovial sarcoma.