MMP9 and ovarian cancer: This overexpression controls lactate production and promotes metastasis and stemness of ovarian cancer cells through focal adhesion kinase (FAK)/extracellular signal-regulated kinase (ERK1/2) activation-induced matrix metalloproteinase 9 (MMP9)/NANOG/SRY-Box 9(SOX9), as demonstrated in ovarian cancer cell lines and clinical samples.