To study the effect of fibroblast SRF on the migration and invasion of cancer cells, we stably transfected the human fibroblast cell line CCD18Co with the human SRF-pTRIPZ vector (Figure 2A, left), collected the serum-free medium (CCD18Co-SRF) 24 hrs after doxycycline induction, and used the conditioned medium (CM) to culture MKN45 GC cells, as illustrated in Figure 2B. Here, SRF is linked to cancer.