Table 4.
Concentration levels of the six lung cancer candidate markers determined using targeted metabolomics analysis in the discovery set and the validation set of samples. LC lung cancer, COPD chronic obstructive pulmonary disease.
| Metabolite | Verification step | Validation step | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| LC group (n = 50) | COPD group (n = 50) | P value | LC group (n = 28) | COPD group (n = 27) | P value | |||||
| Mean (μM) | Median (μM) | Mean (μM) | Median (μM) | Mean (μM) | Median (μM) | Mean (μM) | Median (μM) | |||
| Allantoin | 1.77 | 1.71 | 3.49 | 2.88 | < 0.0001 | 2.22 | 2.07 | 3.95 | 3.84 | < 0.0001 |
| Glutamic acid | 99.97 | 89.55 | 153.4 | 149.5 | < 0.0001 | 109.9 | 103.0 | 166.7 | 159.5 | 0.0001 |
| Inosine | 5.88 | 5.38 | 2.36 | 1.15 | < 0.0001 | 5.54 | 3.72 | 3.60 | 2.96 | 0.2665 |
| Succinic acid | 3.07 | 2.79 | 4.94 | 4.27 | < 0.0001 | 5.00 | 4.49 | 6.31 | 5.83 | 0.0033 |
| Sphingosine-1-Phosphate (d18:1) | 0.71 | 0.68 | 0.92 | 0.90 | < 0.0001 | 0.81 | 0.77 | 0.97 | 0.96 | 0.0074 |
| 1–2-Dioleoylglycerol | 10.79 | 8.81 | 6.57 | 4.33 | 0.0011 | 18.50 | 16.19 | 15.83 | 15.74 | 0.4953 |