Epithelial-mesenchymal plasticity in tumor immune evasion

Epithelial-mesenchymal transition (EMT) is a fundamental process that occurs during embryogenesis and tissue repair. However, EMT can be hijacked by malignant cells, where it may promote immune evasion and metastasis. Classically considered a dichotomous transition, EMT in cancer has recently been considered a plastic process whereby malignant cells display and interconvert among hybrid epithelial/mesenchymal (E/M) states. Epithelial-mesenchymal plasticity (EMP) and associated hybrid E/M states are divergent from classical EMT with unique immunomodulatory effects. Here, we review recent insights into the EMP-immune crosstalk, highlighting possible mechanisms of immune evasion conferred by hybrid E/M states and roles of immune cells in EMP.