Biomarkers in Exhaled Breath Condensate and Serum of Chronic Obstructive Pulmonary Disease and Non-Small-Cell Lung Cancer

Table 1

Summary of EBC markers of oxidative stress and antioxidant capacity including S100 proteins in COPD and lung cancer (legend: “↑”: elevated, “↓”: decreased, “≈”: no difference, “×”: undetectable).

Category	Biomarkers	COPD patients		Lung cancer patients
		EBC (compared to healthy volunteers)	EBC (compared to smokers or ex-smokers)	EBC (compared to healthy volunteers)	EBC (compared to specific controls)
Markers of oxidative stress
Reactive oxygen species	Hydrogen peroxide	↑ [34, 135–138]	↑ [34]	↑ [135]
Reactive nitrogen species	Nitric oxide	↑ [139–144]	↑ [139, 141]	↑ [140]	↑ (controls = cancer patients) [142]
	Nitrite	↑ [145]	↑ [145]		↑ (controls = cancer patients) [142]
	Nitrate	High variability [146]			↓ (controls = cancer patients) [142]
		≈ [141, 147]
	Peroxynitrite	↑ [148, 149]	↑ [148, 149]
Lipid peroxidation products/eicosanoids (arachidonic acid derivatives)	8-isoprostane	↑ [137, 148, 150, 151]	↑ [34, 148, 150]		↑ [135]
					≈ (controls = healthy smokers) [152]
	Malondialdehyde	↑ [138, 153]	↑ [153]	↑ [154]
		≈ [137, 155]	≈ [137]
	Leukotrienes B4	↑ [156–158]	↑ [159]		↑ (controls = patients without pulmonary disease) [156]
	Leukotriene C4			↑ [160]
	Leukotriene D4			↑ [160]
	Leukotriene E4	≈ [158]		↑ [160]
	Prostaglandin E2	↑ [158]
	Thromboxane B2 (the stable form of thromboxane A2)	↓ [158]
	Prostaglandin D2-methoxime	≈ [158]
	Prostaglandin F2α	↑ [158]
Cytokines and proteins	Tumour necrosis Factor-α	≈ [47]		↑ [161]	↑ (controls = smokers without COPD or lung cancer) [152]
	Interleukin-6	↑ [162]		↑ [163]
		≈ [47]
	Interleukin-8	≈ [47, 164]	≈ [164]		↑ (controls = patients without pulmonary diseases) [156]
	Metaloproteinase-9		↑ [134]		↑ (controls = patients without pulmonary diseases) [165]
	Vascular endothelial growth factor				↑ (controls = healthy smokers) [152]
	Endothelin-1	↑ [166]		↑ [167]
				↑ [168]
Volatile organic compounds	Alkanes, alkane derivatives, benzene derivatives	↑ (exhaled ethane) [169]		↑ [170, 171]
Heme breakdown product	Carbon monoxide	↑ [144]	↑ [144]
pH		↓ [164, 172–175]	≈ [173]	≈ [172]
Deoxyribonucleic acid mutations	3p microsatellite alterations			↑ [176]
	Tumour suppressor gene P53 mutations			↑ [177]
	Oncogene KRAS			↑ [178]
	Epidermal growth factor receptor (EGFR) gene mutations			↑ (in small number of heavy smokers with squamous cell carcinoma) [179]
	Gene promoter methylation mutations			↑ [180]
	Mitochondrial DNA mutations				↑ (controls = smokers, exsmokers without chronic respiratory diseases, respiratory illnesses, or lung cancer) [70]
Viruses	Human papilloma virus				↑ (controls = patients suspected of lung cancer but with negative cytology) [181]
Markers measuring antioxidant capacity
Enzymes	Superoxide dismutase				↑ (controls = patients without pulmonary diseases) [182]
Nonenzymatic antioxidants	Ascorbic acid/vitamin C			↓ (↑ in percentage degradation/oxidation rate) [161]
	Urate	× [175]	× [175]
	Ferritin				↑ (controls = patients affected by transudative pleural effusion and without pulmonary diseases) [182]
	Bilirubin	≈ [175]	≈ [175]