Similarly, Aboussekhra and colleagues demonstrated that SDF-1/MMP-2 secreted by cancer-associated fibroblasts deficient in p16 could induce an EMT in MDA-MB-231 breast cancer cells, again suggesting mechanisms of paracrine regulation of EMT in breast cancer (Al-Ansari et al., 2013). The gene discussed is CXCL12; the disease is breast carcinoma.