High HOTAIR lncRNA expression promotes the secretion of monocyte chemoattractant protein-1 (MCP-1/CCL2) by tumor cells and promotes the proliferation of tumor-associated macrophages (TAM) and myeloid-derived suppressor cells (MDSC) in the immune microenvironment (Botti et al., 2019). The gene discussed is CCL2; the disease is neoplasm.