The lung-metastatic (LM) cell lines showed an increased gene expression of integrin α-1, α-4, α-5, α-6, α-V, and β-1, E-cadherin,and MMP-1, -2, -3, -11, -16, and -24 compared with wild-type MDA-MB-231 breast cancer cells (WT) as shown in Figure 1b.34 It should be noted here that tail vein injected breast cancer cells represent a subpopulation of cancer cells with increased tendency to colonize a particular organ.35 Here, MMP1 is linked to cancer.