Fig. 6. Summary of mechanisms underlying treatment failure.

a, Diagram of the steps involved in a successful T cell-mediated anti-tumor response: (1) Initial TIL infiltration, antigen presentation and clonal expansion. (2) Antigen presentation in the lymph nodes and activation/replication of T cells. (3) Clonal expansion and T cell activation in the blood post-treatment. (4) Immune suppression by Treg cells in the TME after treatment. b, Summary of each patient who failed therapy compared with the average responder. No evidence of a step in a patient is depicted with ‘−’, some evidence of a step is indicated with ‘+’ and a lot of evidence of a step is indicated with ‘++’. TDLN, tumor draining lymph node.