In another comprehensive study, Takahara et al. demonstrated that TGF-β1 mRNA expression is significantly elevated in ccRCC tissues compared to adjacent normal kidney tissues, with high TGF-β1 levels correlating strongly with higher WHO/ISUP nuclear grade, increased tumor necrosis, and an enhanced likelihood of distant metastasis. Here, TGFB1 is linked to nonpapillary renal cell carcinoma.