CCL2 and cancer: Moreover, NF-κB pathway activation is proved to be important for the paracrine function of tumor-derived-MSCs and cancer-associated fibroblasts in lung cancer and breast cancer in secreting CCL2, IL-6, and IL-8 in the tumor microenvironment (Katanov et al., 2015; Li et al., 2016; Bai et al., 2017; Su et al., 2018).