SPP1 and clear cell sarcoma of kidney: A 2023 study focused on a rare pediatric renal tumor, clear cell sarcoma of the kidney (CCSK), showed that tumors with the BCOR internal tandem duplication (ITD), which is the most common driver mutation in CCSK, exhibit increased JUND expression (as well as increased Fibroblast growth factor 3 [FGF3], Vascular endothelial growth factor A [VEGFA], Secreted phosphoprotein 1 [SPP1], and Adrenomedullin [ADM]) [181] (Table 6).