Table 5. Non-blood-based diagnostic biomarkers of GC from saliva, gastric juice, urine, and stool.
| Biosources | Biomarkers | No. of participants (GC/control) | Methods | Sensitivity (%) | Specificity (%) | AUC | Reference | |
|---|---|---|---|---|---|---|---|---|
| Saliva | ||||||||
| miRNAs + mRNAs | 3 mRNAs (SPINK7, PPL, and SEMA4B) and 2 miRNAs (miR140-5p and miR301a) | 163/131 | qRT-qPCR | 75.0 | 83.0 | 0.810 | Li et al. (2018) [115] | |
| mRNAs | mRNAs (SPINK7, PPL, SEMA4B, SMAD4) | 200/200 | Luminex xMAP assay + qRT-PCR | 94.0 | 91.0 | NP | Xu et al. (2020) [116] | |
| Proteins | CSTB, TPI1, and deleted in DMBT1 | 40/40 | TMT technology | 85.0 | 80.0 | 0.930 | Xiao et al. (2016) [117] | |
| Protein glycosylation | SBA and VVA | 87/134 | Lectin microarrays | 96.0 | 80.0 | 0.890 | Shu et al. (2017) [118] | |
| Microbiota | Bacterial genera | 99/194 | 16S rRNA gene sequencing | NP | NP | 0.910 | Huang et al. (2021) [119] | |
| Gastric juice | ||||||||
| miRNAs | miR-129-1-3p, miR-129-2-3p | 42/99 | qRT-PCR | 68.7 | 71.9 | 0.656 | Yu et al. (2013) [120] | |
| miR-21, miR-106a | 42/99 | qRT-PCR | 85.7, 73.8 | 97.8, 89.3 | 0.969, 0.871 | Cui et al. (2013) [121] | ||
| miR-133a | 62/142 | qRT-PCR | 85.9 | 84.8 | 0.907 | Shao et al. (2016) [122] | ||
| lncRNAs | AA174084 | 39/92 | qRT-PCR | 46.0 | 93.0 | 0.848 | Shao et al. (2014) [123] | |
| RMRP | 39/92 | qRT-PCR | 56.4 | 75.4 | 0.699 | Shao et al. (2016) [124] | ||
| ABHD11-AS1 | 39/92 | qRT-PCR | 41.0 | 93.4 | 0.650 | Yang et al. (2016) [125] | ||
| piRNAs | piR-1245 | 66/66 | qRT-PCR | 90.9 | 74.2 | 0.885 | Zhou et al. (2020) [126] | |
| Exosomal DNAs | BARHL2 methylation | 20/10 | ExoQuick-TC, Bisulfite PCR | 90.0 | 100.0 | 0.923 | Yamamoto et al. (2016) [127] | |
| Urine | ||||||||
| DNA | 8-OHdG and 8-OHG | 60/70 | SPE and UPLC-MS/MS | NP | NP | 0.777 and 0.841 | Chen et al. (2020) [128] | |
| miRNAs | miR-376c | 65/108 | qRT-PCR | 60.0 | 64.0 | 0.700 | Hung et al. (2017) [34] | |
| miR-6807-5p, miR-6856-5p, and Helicobacter pylori | 153/153 | qRT-PCR | 76.9 | 88.9 | 0.885 | Iwasaki et al. (2019) [129] | ||
| MMP-9/NGAL and ADAM12 | 35/35 | NP | NP | 0.825 | Shimura et al. (2015) [130] | |||
| Proteins | Endothelial lipase | 90/57 | Western blotting | 79.0 | 100.0 | 0.970 | Dong et al. (2013) [131] | |
| TFF1, ADAM12, H. pylori (male) | 144/138 | Quantitative proteomics analysis | NP | NP | 0.858 (male), 0.893 (female) | Shimura et al. (2020) [132] | ||
| TFF1, uBARD1, H. pylori (female) | ||||||||
| Stool | ||||||||
| Microbiome | Veillonella, Megasphaera, and Prevotella 7 genus and Streptococcus salivarius subsp. Salivarius, Bifidobacterium dentium, and Lactobacillus salivarius | 134/58 | GC-MS | NP | NP | 0.694–0.837 | Wu et al. (2020) [133] | |
| Desulfovibrio, Escherichia, Faecalibacterium, or Oscillospira | 38/35 | qPCR | NP | NP | 0.900–0.920 | Liu et al. (2021) [134] | ||
GC = gastric cancer; AUC = area under the curve; miRNA = microRNA; mRNA = messenger RNA; qRT-qPCR = quantitative reverse transcription quantitative real-time polymerase chain reaction; qRT-PCR = quantitative reverse transcription polymerase chain reaction; NP = not presented; TMT = Tandem Mass Tags; lncRNA = long non-coding RNA; piRNA = PIWI-interacting RNA; PCR = polymerase chain reaction; SPE = solid phase extraction; UPLC-MS/MS = ultra performance liquid chromatography-tandem mass spectrometry; GC-MS = gas chromatography-mass spectrometry; qPCR = quantitative polymerase chain reaction.