Volatile organic compound (VOC) breath testing in cancer detection The concept for VOC testing is that VOCs, mostly alkanes and aromatic compounds, are preferentially produced and exhaled by cancer patients and can be used as accurate markers of malignancy. As early as 1971, testing on normal breath identified more than 100 volatile organic compounds In the 1980s Gordon and Preti used mass spectroscopy and gas chromatography to identify specific alterations in the profile of volatile organic compounds in the breath of lung cancer patients[16]. In two papers in 1999 and 2003, Phillips further refined this original data to identify a group of 9 volatile organic compounds which were highly sensitive and specific for the presence of lung cancer . The concentration of these alkane and methylalkane oxidative stress products was reduced in the breath of lung cancer patients.