Abstract
A recent Phase 1 clinical study of the immunological effects of inhibiting the chemokine receptor, CXCR4, in patients with pancreatic ductal adenocarcinoma or colorectal cancer suggests that stimulation of CXCR4 on immune cells suppresses the intratumoural immune reaction. Here, we discuss how CXCR4 mediates this response, and how cancer cells elicit it.