There have different opinions about which type of material in the conditioned medium plays the role, Da-Won Choi et al. reported that some cytokine including Dkk-1, Dkk-3 and IGFBP-3 in conditioned medium play an antitumor role [57], Hamidreza Aboulkheyr Es et al. reported that CCL5, which is a cytokine in Human adipose derived MSCs conditioned medium impeded invasiveness and immune-suppressive characteristics of breast cancer cells[58]. Here, DKK1 is linked to breast cancer.