evidence: A cancer vaccine that had little success in clinical trials for patients with advanced tumors could potentially have efficacy if administered earlier in the treatment cycle, according to a study from Vanderbilt researchers. [...] Philip and colleagues investigated a vaccine previously tested in human clinical trials for advanced cancers. This vaccine uses a gram-positive intracellular bacterium that induces strong CD4 and CD8 T cell responses, and it is engineered to express the tumor epitope, which boosts tumor-reactive T cells. All mice that received vaccination at an early stage remained tumor free, but the vaccine failed to slow liver tumor progression when administered at a later point (age 100 days).