Furthermore, tumor samples generated from MTHFD2 knockdown HGC27 and MKN74 cells as well as PDX-induced tumors suggested limited cell proliferation ability and reinforced cell death compared with control group, as determined by Ki67, caspase 3 activity, cleaved caspase 3 and TUNEL staining, respectively (Figure 4(G–H), Supplementary Figure 2D–E). This evidence concerns the gene MKI67 and neoplasm.