NNMT and gastric cancer: We randomly selected four prognostic signature articles of gastric cancer in the latest 3 years from the PubMed website (https://pubmed.ncbi.nlm.nih.gov/), including Dai’s signature (ITGAV, DAB2, SERPINE1, MATN3, and PLOD2), Liu’s signature (NOX4, NOX5, GLS2, MYB, TGFBR1, NF2, AIFM2, ZFP36, SLC1A4 TXNIP, CXCL2, HAMP, and SP1), Meng’s signature (CGB5, IGFBP1, OLFML2B, RAI14, SERPINE1, IQSEC2, and MPND), and Yin’s signature (GPX3, ABCA1, NNMT, NOS3, SLCO4A1, ADH4, DHRS7, and TAP1) (Meng et al., 2020; Liu SJ et al., 2021; Dai et al., 2021; Yin et al., 2021).