The significant lag time (about 60 s) required for the Streptamer to decay into monomeric pMHC molecules after addition of free d-biotin as well as the photobleaching effect associated with the microscopic assay prevent for the precise determination of rapid TCR–pMHC off-rates, which are typically found within the self/tumor-specific CD8 T cell repertoires of lower TCR affinities. This evidence concerns the gene CD8A and neoplasm.