C-C motif chemokine ligand 2 (CCL2) enhances CSC self-renewal and expansion through the signal transducer and activator of transcription 3 (STAT3) and neurogenic locus notch homolog protein 1 (NOTCH-1) signaling pathways and promotes breast tumor growth and metastasis 93, 94. This evidence concerns the gene STAT3 and breast neoplasm.