CTLA4 and neoplasm: In the G.O. enrichment analysis of the CTLA4+ T cell upregulated gene, we found that S100A4 is associated with epithelial to mesenchymal transition, positive regulation of I-kappaB kinase/NF-kappaB signaling, and mesenchymal cell differentiation, which are tumor stem cell-associated biological processes, and there are also related studies suggesting that S100A4 is a potential factor in regulating tumor stem cells [27].