MMP9 and breast cancer: In breast cancer, elevated BACH1 suggests poor prognosis and facilitates cell migration and invasion via regulating mitochondrial metabolism reprogramming and metastasis-associated genes, such as matrix metalloproteinase-9 (MMP9), vascular endothelial growth factor receptor (VEGFR), and C‐X‐C chemokine receptor type 4 (CXCR4) 8-10.