Significance: Patients with microsatellite stable (MSS) pancreatic (PDA) or colorectal cancer (CRC) do not respond to immunotherapy with inhibitors of T cell checkpoints. A possible explanation is suggested by finding that cancer cells in these tumors are coated with the chemokine, CXCL12, and that stimulation of CXCR4, the CXCL12 receptor on immune cells, suppresses directed migration mediated by other chemokine receptors on these cells. We assessed the relevance of these findings by treating patients for seven days with continuous infusion of AMD3100/Plerixafor, a CXCR4 inhibitor. Comparison of pre- and end-of-treatment paired biopsies of metastatic lesions by transcriptomic analysis revealed that AMD3100 induced an integrated immune response that is predictive of a clinical response to T cell checkpoint inhibition.

Cancer is a major cause of global mortality, both in affluent countries and increasingly in developing nations. Many patients with cancer experience reduced life expectancy and have metastatic disease at the time of death. However, the more precise causes of mortality and patient deterioration before death remain poorly understood. This scarcity of information, particularly the lack of mechanistic insights, presents a challenge for the development of novel treatment strategies to improve the quality of, and potentially extend, life for patients with late-stage cancer. In addition, earlier deployment of existing strategies to prolong quality of life is highly desirable. In this Roadmap, we review the proximal causes of mortality in patients with cancer and discuss current knowledge about the interconnections between mechanisms that contribute to mortality, before finally proposing new and improved avenues for data collection, research and the development of treatment strategies that may improve quality of life for patients.