DKK1 and small cell osteogenic sarcoma: Quantitative real-time PCR revealed that BMP2, DKK1, FGF5, IGF2, MET, PNP, SEMA3A, SPRY2, WNK4, and TJP2 were statistically downregulated in human Sertoli cells of SCOS patients compared to OA patients (Fig. 3a).