T cells play a critical role in tumor immunosurveillance by eliminating newly transformed somatic cells,thereby protecting the host from cancer.However,tumor cell variants can escape from immunological control after immunoediting,leading to the progression of clinically apparent disease.Whether T cells can respond to immunoedited tumor cells and still have impact on tumor progression remains largely unknown.Here,we found that tumor-infiltrating T cells were activated and exhibited persistently up-regulated expression of the activator protein-1 (AP-1) subunit c-Fos during tumor progression.