TKTL1 and cancer: ACRG, Asian Cancer Research Group; CIMP, CpG island methylation phenotype; CIN, chromosomal instability; CNA, copy number alteration; CSC, cancer stem cell; EBV, Epstein–Barr virus; EMT, epithelial‐to‐mesenchymal transition; GC, gastric cancer; GS, genomically stable; MSI, microsatellite instability; MSS, microsatellite stable; TCGA, The Cancer Genome Atlas; TKR, tyrosine kinase receptors.