CCL5 and neoplasm: MSC2 enhances tumour growth and metastasis while MSC1 does not.106 MSCs can enhance tumour progression via the VEGF pathway and the secretion of CCL5, but their effects on tumour vary under different conditions.107, 108 For example, they promote the growth of breast cancer through the WNT signalling.109 In a xenograft ovarian carcinoma model, Spaeth et al.