Similarly, co-culture of human normal lung fibroblasts (NHLF) with human breast cancer cells MCF7 and Hs 578T also induced fibroblasts’ senescence, as represented by p21 and p27 upregulation, β-galactosidase staining and ki-67 loss, as well as pR6S increase [22] (Fig. 5E and F, sFig. 4D to 4F). Here, MKI67 is linked to breast carcinoma.