Volatile S-nitrosothiols and the typical smell of cancer

An unconventional approach to investigations into the identification of typical volatile emissions during illnesses gives rise to the proposal of a new class of cancer markers. Until now, cancer markers seem not to have been conclusively identified, though the obvious behavior of dogs points to their existence. The focus has been directed towards molecules containing sulfurous functionalities. Among such compounds, S-nitrosothiols (SNOs) are known to be involved in important physiological processes in living organisms and they are described as being typically elevated in cancer. Volatile SNOs (vSNOs) are proposed to be the source of the significant smell of cancer. Synthetic vSNOs are known to have lifetimes of between some minutes and several hours, which may be the main reason as to why they have been ignored until now, and also for the inability of analytics to detect them in vivo. Based on typical structures occurring in the volatile sulfur organics being emitted from human breath, four vSNOs have been synthesized and characterized by tandem mass spectrometry and gas chromatography/mass spectrometry. Simulating the relatively fatty consistency of cancer tissue by diluting the samples in n-decane, surprisingly reduces their tendency to decompose to lifetimes of weeks even at room temperature. A sniffer dog was trained with the synthetic vSNOs, and the results of the tests indicate that synthetic and cancer smells are very similar or even the same. The findings can be a clue for further target-oriented systematic optimization of existing sensitive measurement methods to prove vSNOs as cancer emissions and finally establish future methods for cancer diagnosis based on screening for this new class of volatile illness markers.