Similarly, Ma et al. reported that IL-8 and IL-6 secreted by umbilical cord MSCs activated the autocrine IL-8 and IL-6 signalling in breast cancer cell line (MCF-7) and induced CD44(+)/CD24(−) cells, which consequently promoted MCF-7 cell migration in vitro and metastasis in vivo49. Here, CD44 is linked to breast cancer.