CCL2 and HGF expression are modulated by cytokines such as TGF-β.44,45 In breast cancer, CCL2 is regulated at the transcriptional level by EGR1, RXRA and PARP.44,46 In addition, CCL2 is regulated post-transcriptionally by miRNAs47,48 and long non-coding RNAs.49 On the other hand, HGF gene expression is regulated by SP transcription factors50 and at the post-transcriptional mechanisms through miR-199a.45 These data indicate that CCL2 and HGF are induced by similar cytokines but may be regulated differently downstream at the transcriptional and post-transcriptional levels. Here, RXRA is linked to breast cancer.