REG4 and neoplasm: - CAFs in RCRC uniquely express AGR2, a protein that potentiates VEGF and FGF2 signaling to drive endothelial cell proliferation and angiogenesis- Right-sided CAFs are characterized by the overexpression of REG4, which exacerbates tumor invasion, and transcription factors E2F1 and FOXF1, which promote rapid tumor growth by activating the “cell cycle” and “apoptosis” pathways, with FOXF1 also contributing to neovascularization