IFNG and cancer: In contrast to the detection of p53-specific CD4+ T cells in seropositive and seronegative cancer patients as well as in healthy donors, our presensitization protocol only allows detection of NY-ESO-1-specific IFN-γ-producing CD4+ T cells in NY-ESO-1 seropositive cancer patients but not in seronegative cancer patients and healthy individuals when PBMC-derived whole CD4+ T cells are presensitized with NY-ESO-1 overlapping peptides.