TAP1 and neoplasm: We then addressed the question of whether ppCT9–17, ppCT50–59 and ppCT91–100 were naturally processed by tumour cells by testing the capacity of responding T cell lines to recognize the ppCThighTAPlow IGR-Heu cell line generated from patient 1 (Heu) and the IGR-Heu-TAP cell line, which we had previously transfected with TAP1/2-encoding plasmids23.