MMP9 and urinary bladder cancer: Mechanistically, protein tyrosine kinase 6 (PTK6)‐mediated phosphorylation of ETS variant transcription factor (ETV4) enhances bladder cancer (BCa) cells‐derived chemokine C‐X‐C motif ligand (CXCL)1/8 to recruit TANs, leading to the increase of vascular endothelial growth factor A (VEGFA) and matrix metalloproteinase‐9 (MMP9), and then facilitating lymphangiogenesis and LN metastasis of bladder cancer.