Can proteomics predict the prognosis in chronic dioxin intoxication?

Untargeted proteomic analysis of exhaled breath condensate (EBC) was used to estimate the effects and prognosis of chronic intoxication with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to elucidate the mechanisms involved. EBC was collected from eight males (72.4 ± 1.3 years) exposed to TCDD in 1965–1968 and seven control males (66 ± 16 years). The median TCDD blood level was 112 (46–390) ng/kg fat in the patients 50 years after exposure and 12 ng/kg in the controls. The shotgun method for identifying proteins was performed after proteolytic digestion and high-performance liquid chromatography combined with mass spectrometry. Raw data were evaluated using the MaxQuant software and protein atlas. A total of 332 proteins were detected: one protein was unique to TCDD patients and 11 to the controls. These proteins may have come from many organs, in addition to the lungs and bronchi. The salivary contribution based on alpha amylase proportion to the overall protein's intensity was only 0.003%. The intensity of nine proteins was correlated with TCDD plasma level (two positively, seven negatively), but not with alpha amylase. This excludes saliva contamination, as this enzyme is the marker of salivary contamination. Several of the changes in intensity were associated with an unfavourable prognosis of cancers. Proteomics of EBC may bring new information and point to the mechanisms by which this highly toxic chemical and human carcinogen potentially affects any organ. Graphic abstract:

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