Not only can the gene copy number of KCNK12 allow it to serve as a molecular biomarker for the early detection of diseases (acute lymphoblastic leukemia (Han and Kang, 2009), non-Hodgkin’s lymphoma (Han and Kang, 2009), tubular breast carcinoma (Riener et al., 2008), synovial sarcoma (Heidecker et al., 2010), and malignant peripheral nerve sheath tumors (Nakagawa et al., 2006)) but the expression of these two-pore domain potassium channels also holds promise as an index for therapeutic targets. This evidence concerns the gene KCNA3 and synovial sarcoma.