More Evidence That Tumor Exosomes Pave the Way for Metastasis

from NEJM Watch by Anthony L. Komaroff

An international team led by researchers at Weill Cornell Medicine, now reports that both mouse and human tumors that characteristically home to certain organs — lung, liver and brain — secrete exosomes that also home to those organs. Primary tumors destined to home to liver, for example, secrete exosomes with specific integrin molecules on their surface that bind ligands on various types of liver cells. Exosome contents were ingested by liver cells, triggering a cascade of molecular events that made the liver hospitable to implantation and growth of circulating malignant cells from the primary tumor. The specificity of the exosomes was remarkable: When mice were first injected with exosomes that home to liver and then given tumor cells that normally home to bone, those cells metastasized to liver, not bone. Blocking specific exosome integrins with decoy molecules prevented metastasis to specific organs.

Exosomal integrin expression as a potential predictor of patient organ-specific metastasis

Source – NEJM Watch