IFNG and neoplasm: Although the T-cell line G1 showed highly cytotoxic activity against HLA-DR-matched tumor cell lines HSC-4 and Lu65, but not against HLA-DR-unmatched tumor cell line Sa-3, pretreatment of tumor cell lines with IFN-γ was required for upregulating both HLA-DR and PD-L1 (Fig. 5a).