IFNG and colorectal carcinoma: A similar high or variable background IFNγ secretion was found in the response of PBMC to no peptides from the four CRC patients (0.14% ± 0.21% for CD4 and 0.19% ± 0.35% for CD8 T cells) and in the four HD blood samples (0.05% ± 0.05% for CD4 and 0.09% ± 0.16% for CD8 T cells) (not shown).