Table 1 Systematic search strategy (PICOS strategy)

Participant

#1 (Stomach Neoplasms[MeSH Terms] OR”Neoplasm, Stomach"OR"Stomach Neoplasm"OR"Neoplasms, Stomach"OR"Stomach Neoplasms"OR"Gastric Neoplasms"OR"Gastric Neoplasm"OR"Neoplasm, Gastric"OR"Neoplasms, Gastric"OR"Cancer of Stomach"OR"Stomach Cancers"OR"Gastric Cancer"OR"Cancer, Gastric"OR"Cancers, Gastric"OR"Gastric Cancers"OR"Stomach Cancer"OR"Cancer, Stomach"OR"Cancers, Stomach"OR"Cancer of the Stomach"OR"Gastric Cancer, Familial Diffuse”)

Index test

#2 (RNA, Long Noncoding[MeSH Terms]OR“RNA, Long Noncoding”OR“Noncoding RNA, Long”OR”lncRNA”OR”Long ncRNA”OR”ncRNA, Long”OR”RNA, Long Non-Translated”OR”Long Non-Translated RNA”OR”Non-Translated RNA, Long”OR”RNA, Long Non Translated”OR”Long Non-Coding RNA”OR”Long Non Coding RNA”OR”Non-Coding RNA, Long”OR”RNA, Long Non-Coding”OR”Long Non-Protein-Coding RNA”OR”Long Non Protein Coding RNA”OR”Non-Protein-Coding RNA, Long”OR”RNA, Long Non-Protein-Coding”OR”Long Noncoding RNA”OR”RNA, Long Untranslated”OR”Long Untranslated RNA”OR”Untranslated RNA, Long”OR”Long ncRNAs”OR”ncRNAs, Long”OR”Long Intergenic Non-Protein Coding RNA”OR”Long Intergenic Non Protein Coding RNA”OR”LincRNAs”OR”LINC RNA”)

Comparison

None

Outcome

#3 (Biomarkers[MeSH Terms]OR“Biomarkers”OR”Biomarker”OR”Markers, Biological”OR“Biologic Markers”OR“Markers, Biologic”OR“Biologic Marker”OR“Marker, Biologic"OR“Marker, Biological”OR“Biological Marker”OR“Biological Markers”OR“Markers, Laboratory”OR“Laboratory Markers”OR“Laboratory Marker”OR“Marker, Laboratory”OR“Serum Markers”OR“Markers, Serum”OR“Marker, Serum”OR“Serum Marker”OR“Plasma Markers”OR“Markers, Plasma”OR“Marker, Plasma”OR“Plasma Marker”OR“Markers, Clinical”OR“Clinical Markers”OR“Clinical Marker”OR“Marker, Clinical”)

#4 (Sensitivity and Specificity[MeSH Terms]OR“Sensitivity and Specificity”OR“Specificity and Sensitivity”OR”Sensitivity”OR”Specificity”) OR (Diagnosis[MeSH Terms]OR“Diagnosis”OR“Diagnose”OR”Diagnostic”OR“Diagnoses”OR”Diagnoses and Examinations”OR”Examinations and Diagnoses”OR”Postmortem Diagnosis”OR”Diagnoses, Postmortem”OR”Diagnosis, Postmortem”OR”Postmortem Diagnoses”OR”Antemortem Diagnosis”OR”Antemortem Diagnoses”OR”Diagnoses, Antemortem”OR”Diagnosis, Antemortem”)

Study design

None

Search

#1 AND #2 AND (#3 OR #4)

Language

No restriction

Electronic databases

PubMed, Web of Science, Cochrane Library, and Embase databases