A report demonstrated that CCL2 is an essential factor for the recruitment of macrophages and the accumulation of MDSC in the tumor milieu (81, 126, 139, 140), signifying that the overexpression of HOTAIR in cancer cells results in TAMs/MDSCs recruitment through CCL2 release, leading to augmented tumor progression and metastasis (127). This evidence concerns the gene HOTAIR and neoplasm.