Among the MMPs, MMP-2 and MMP-9 are strongly correlated with tumor invasion and metastasis in breast cancers (Li et al., 2017), as MMP-2 is more constitutively expressed in metastatic cancers and MMP-9 is highly inducible by various stimuli (Raeeszadeh-Sarmazdeh et al., 2020). This evidence concerns the gene MMP9 and breast cancer.