IL6 and breast cancer: Adipocyte-derived IL-6 and leptin enhanced the PLOD2 expression by activating the janus tyrosine kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) and phosphatidylinositide 3-kinases (PI3K)/protein kinase B (AKT) signaling pathways, thereby promoting breast cancer metastasis in vivo [27].