CXCR4 and cancer: For example, EMT showed a remarkably high positive correlation with fibroblasts, which are known to play important roles in the EMT process in the tumor microenvironment.45 Several clinical trials related to interference with cancer-associated fibroblasts (CAF) activation, CAF action and CAF normalization are currently underway,46 involving targeting TGFβ, C-X-C motif chemokine receptor 4 (CXCR4) or vitamin A metabolism.