PTGDR and gastric cancer: The risk score for each GC patient was calculated using the following formula: Risk score = (2.120289225 × AC110491.1) + (−0.394086164 × AL355574.1) + (−0.373467544 × RHPN1-AS1) + (1.245072128 × AOAH-IT1) + (0.450022303 × AP001065.3) + (−3.793874086 × MEF2C-AS1) + (−0.520167444 × AC016394.2) +(0.764878872 × LINC00705) + (0.7858314 × LINC01952) + (0.382918529 × PART1) + (−0.408911862 × TNFRSF10A-AS1) + (1.78093689 × LINC01537).