CD8A and colorectal carcinoma: Another preclinical study in the same model showed that the combination of FTD/TPI with an anti-PD-1 antibody improved tumour regression compared with either agent alone, indicating synergistic activity of the combination in MSS CRC, and suggesting a potential immune effect of FTD/TPI in CRC.24 Furthermore, increased tumour immunogenicity is observed with a higher CD8/Treg ratio with the use of the combination.