Our previous work revealed the presence of the NY-ESO-1 transgenic TCR in both the metastatic and recurrent lesions using T-cell receptor sequencing (TCRseq), indicating that the infusion product successfully trafficked to both sites and remained present following disease progression.2 We further interrogated TCRseq data derived from the infusion products, and tumor samples to define the clonal dynamics across the two clinical trial protocols and disease progression. This evidence concerns the gene TBXT and neoplasm.