One mechanism by which MSCs can inhibit tumour growth is through the different mediators secreted by these cells, which is supported by a study on animal models of human hepatoma, where an increase in tumour cell apoptosis was observed through the down‐regulation of Bcl‐2, c‐Myc and proliferating cell nuclear antigen (PCNA) (Qiao et al., 2008). The gene discussed is PCNA; the disease is hepatocellular carcinoma.