CXCL1 and neoplasm: Moreover, cytokines secreted by senescent cells such as interleukin-6 (IL-6) and C-X-C pattern chemokine ligand 1 (CXCL1) are also shown to promote tumor development by stimulating endothelial cell proliferation, promoting angiogenesis, facilitating tumor cell invasion, or inducing cancer stem cell formation (Liu et al., 2018).