PRF1 and neoplasm: However, it is also notable that a series of genes that are expressed in activated CD8+ T cells (Gzmb, Prf1, Il2, Ifng, Tnf, Fasl) or in activated CD4+ T cells (Tgfb1, Cd40lg, Il2, Ifng, Tnf, Fasl) were not upregulated in the relevant CD8+ and CD4+ clusters in tumours versus normal (Supplementary Fig. 3a,b).