Table 3.

Results of volcano plot analysis for RP-LC dataset. Important metabolic features (marker candidates) occurring in all types of comparisons between lung cancer (LC) patients and chronic obstructive pulmonary disease (COPD) patients were bolded. Directions of comparison in fold change analysis: LC/COPD when grouping variable was cancer status; current smokers/former smokers when grouping variable was smoking status.

The grouping variable—cancer status
A. LC vs COPD all patients			B. LC vs COPD current smokers			C. LC vs COPD former smokers
Metabolite	Fold change	FDR-adjusted P value	Metabolite	Fold change	FDR-adjusted P value	Metabolite	Fold change	FDR-adjusted P value
Sphingosine-1-phosphate (d18:1)	0.69	< 0.0001	Sphingosine-1-phosphate (d18:1)	0.68	0.0002	1,2-Dioleoylglycerol	1.42	0.0149
1,2-Dioleoylglycerol	1.44	< 0.0001	Lyso-PAF C-16	0.69	0.0004	Sphingosine-1-phosphate (d18:1)	0.71	0.0149
Lyso-PAF C-16	0.72	< 0.0001	Arachidonic acid	0.70	0.0018
2-O-Ethyl PAF C-16	0.75	< 0.0001	2-O-Ethyl PAF C-16	0.73	0.0030
Sphinganine-phosphate (d18:0)	0.72	0.0003	Stearoylethanolamide	0.74	0.0055
1-Linoleoylglycerol	1.97	0.0006	Sphinganine-phosphate (d18:0)	0.72	0.0063
1-Arachidonoylglycerol	2.00	0.0022	1-Linoleoylglycerol	0.32	0.0086
Chenodeoxycholic acid	0.31	0.0030	1,2-Dioleoylglycerol	0.68	0.0094
Arachidonic acid	0.76	0.0037	1-Arachidonoylglycerol	0.31	0.0215
Eicosapentaenoic acid	0.67	0.0125	Eicosapentaenoic acid	0.62	0.0306
			Ceramide (d18:1/14:0)	0.74	0.0359

The grouping variable—smoking status
D. current smokers vs former smokers			E. LC current smokers vs LC former smokers			F. COPD current smokers vs COPD former smokers
Metabolite	Fold change	FDR-adjusted P value	Metabolite	Fold change	FDR-adjusted P value	Metabolite	Fold change	FDR-adjusted P value
No records found	–	–	Adrenic acid	0.72	0.0436	No records found	–	–