MMP9 and prostate cancer: Besides, a recent study found that binding of extracellular S100A4 to embigin (a transmembrane glycoprotein belonging to the immunoglobulin superfamily) mediated prostate cancer progression by inhibition of adenosine monophosphate‐activated protein kinase (AMPK) activity, activation of nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB), MMP‐9 and mammalian target of rapamycin complex 1 (mTORC1) signalling, and inhibition of autophagy, which increased prostate cancer cell motility.57