GPC3 and neoplasm: Interestingly, CTL generated by DC loaded with peptide 5 effectively lysed HepG2 cells, indicating that it was expressed in association with HLA-A2 on the surface of the tumour cells, possibly reflecting differences in the cleavage of the GPC-3 polypeptide by the constitutive proteasome in the tumour cell line and the immunoproteasome in DC [37].