IFNG and cancer: Moreover, we performed an enzyme-linked immunospot (ELISpot) assay stimulating interferon-γ (IFNγ) release by peptide pools of SARS-CoV-2 spike S1 and S2 domains of Delta and partially of Omicron (BA.1) to quantitatively assess the SARS-CoV-2- and seasonal HCoV OC43-directed T cell responses to COVID-19 in 53 of these individuals with cancer.