Cancer Treatment: Identification of the Blood Vessels That Allow Killer Lymphocytes to Access and Destroy Tumors

Microscopic visualization of lymphocytes ( in green ) infiltrating a tumor HEV ( in red ) during combination anti-PD-1 plus anti-CTLA-4 immunotherapy. The white arrow indicates a lymphocyte that is leaving the bloodstream and entering the tumor ( in black ). Elisabeth Bellard and Jean-Philippe Girard - IPBS (CNRS/UT3 Paul Sabatier) Microscopic visualization of lymphocytes ( in green ) infiltrating a tumor HEV ( in red ) during combination anti-PD-1 plus anti-CTLA-4 immunotherapy. The white arrow indicates a lymphocyte that is leaving the bloodstream and entering the tumor ( Immunotherapy, a therapeutic strategy aimed at increasing the activity of the immune system in order to recognize and destroy cancer cells, has revolutionized cancer treatment over the past decade. A better understanding of how this therapeutic approach works, and more particularly how killer lymphocytes access tumors during immunotherapy, could improve the efficacy of the treatments. The team of Jean-Philippe Girard, Inserm Research Director at the Institute of Pharmacology and Structural Biology (French National Center for Scientific Research [CNRS]/Université Toulouse III - Paul Sabatier), in collaboration with Gustave Roussy, has recently discovered the essential role played in this process by specific blood vessels known as tumor-associated HEVs. For the first time, the scientists were able to film the lymphocytes infiltrating the walls of the HEV vessels to enter the tumors.