Fig. 2.

Pex mediates cell–cell communication. CICs lead to reprogramming of non-CICs by secreting Pex. The preferential fusion of Pex with Kupffer cells leads to the recruitment and activation of HSCs, the formation of a fibrotic microenvironment and ultimately to liver metastasis. PaCa activates PSCs by secreting exosomes, and activated PSCs promote PaCa proliferation, metastasis and drug resistance by secreting exosomes. In terms of immune cells, Pex leads to reprogramming of macrophages, recruitment of Tregs, inhibition of NK cells, maturation of MDSCs through signalling molecules and ultimately to immune suppression. (dashed lines: inhibit, solid lines: promote)