Radiation-induced amphiregulin drives tumor metastasis

The anti-tumor effect of radiotherapy (RT) beyond the treatment field - the abscopal effect - has garnered much interest. By contrast, the potentially harmful impact of radiation in promoting metastasis is less well studied. Here, we show that RT induces the expression of epidermal growth factor receptor (EGFR) ligand amphiregulin (AREG) in tumor cells, which reprograms EGFR+ myeloid cells toward an immunosuppressive phenotype and reduces phagocytosis. This stimulates distant metastasis growth in both patients and pre-clinical murine tumor models. The inhibition of these tumor-promoting factors induced by RT may represent a novel therapeutic strategy to improve patient outcomes.