CTLA4 and neoplasm: Taking CD4+ Treg cells and CD8+ cytotoxic T cells as examples, Treg cells derived from tumor tissues showed higher expression of LAYN, LGALS1 and TNFRSF1B, and cytotoxic T cells derived from tumor tissues showed higher expression of TNFRSF9 (encoding 4-1BB), LAYN and CTLA4 (Supplementary Fig. S9c).