SMAD6 and renal cell carcinoma: RCC tissues that successfully generated organoids highly expressed genes associated with stemness (WNT6/11, FZD8/9 and JAG2), cell matrix (MMP2, COL1A1), fatty metabolism (ACOT2, LIPE) and cancer development (TGFB1, SMAD6/7, EGF and FGF1) (Figure S6D).