A series of potential biomarker genes shared with blood- and skin-derived SCs were identified, including reported (TOX, DNM3, and KLHL42) and novel (PGM2L1 and SESN3) tumor-associated genes, which could help to differentiate between SS and erythrodermic inflammatory dermatoses (EIDs), and facilitate the diagnosis and prognosis of MF/SS. Here, KLHL42 is linked to synovial sarcoma.