LIF and synovial sarcoma: Compared with the control tissues (chronic synovitis), the mRNA expression of SOX-2, Nanog, OCT-4, LIF, LIFR and Ki-67 was significantly higher in the synovial sarcoma tissue samples (P = 0.0070, P = 0.0487, P = 0.0002, P = 0.0110, P < 0.0001, and P = 0.0011, respectively) (Fig. 2H).