MMP2 and melanoma: Brain‐metastasizing melanoma cells would stimulate astrocytes to express the pro‐inflammatory interleukin 23 (IL‐23) cytokine which in turn stimulate the secretion of matrix metalloproteinase‐2 (MMP‐2).96 Nevertheless, STAT3 regulates the expression of MMP‐2, both human brain metastatic melanoma cells and tissue biopsies show increased STAT3 activity compared to cutaneous melanoma cells.97 Therefore, increased MMP‐2 secretion by IL‐23 signaling can be mediated through STAT3 to mediate the degradation of extracellular matrix and facilitate extravasation.