Blood-Tumor overlapping TCR repertoire predicts the clinical responses of PD-1 blockade in patients with gastrointestinal cancer [TCR-Seq]

As the anti-PD-1 monoclonal antibody (mAb) becomes to be used in many types of cancers, the needs for the predictive biomarker of PD-1 blockade are growing. T cell receptor (TCR) repertoire—which reflects the anti-tumor T-cell responses based on the antigen specificity—is a potential biomarker of cancer immunotherapy. Here, we analyzed the TCR repertoire of patients with advanced gastrointestinal cancer and explored its association with clinical responses. Overall design: Eight patients with advanced gastrointestinal cancer were treated with an anti-PD-1 monoclonal antibody (nivolumab) every 3 weeks until disease progression. The TCR repertoire of the peripheral blood CD4+ and CD8+ T cells was analyzed once before and three times after the initiation of treatment, whereas in case of tumor biopsy it was analyzed before and after 6 weeks of initiation of the treatment.