Figure 1.

The nuclear receptors phenotype in breast cancer stem cells. In breast cancer, TAF and TAM promote inflammation and invasion through the secretion of cytokines, as IL6, TNFα and TGFβ and the secretion of MMPs, as MMP9. In this hypoxic inflammatory niche, particular stem cells can form the BCSCs as mammospheres. BCSCs are characterized by a particular nuclear receptors phenotype: a lower level of ERα, PPARγ, RARs, RXRs, and a higher level of PPARα is expressed than adherent breast cancer cells. NRs: Nuclear receptors; BCSCs: Breast cancer stem cells; TAF: Tumour associated fibroblast; TAM: Tumour associated macrophage; MMPs: Metalloproteinases; IL6: Interleukin-6; ERα: Estrogen receptor-α; PPARs: Peroxisome proliferator-activator receptors; RARs: Retinoic acid receptors; RXRs: Retinoid x receptors; TNFα: Tumor necrosis factor-α; TGFβ: Trasforming growth factor-β.