CD4 and neoplasm: In line with our findings, previous studies have also reported clinical benefits of pre-existing or therapy-induced circulating IFN-γ-secreting CD4+ T cells against NY-ESO-1, 5T4, SOX2 and HPV-16.15,33–36 These data support that a pre-existing antitumor CD4+ Th1 signature in peripheral blood may confer tumour protection.