An n-alkanal resulting from the oxidation of the alcoholic hydroxy group of heptan-1-ol to the corresponding aldehyde. An endogenous aldehyde coming from membrane lipid oxidation, it is found in the blood of lung cancer patients and has been regarded as a potential biomarker of lung cancer. ChEBI: Heptanal is an n-alkanal resulting from the oxidation of the alcoholic hydroxy group of heptan-1-ol to the corresponding aldehyde. An endogenous aldehyde coming from membrane lipid oxidation, it is found in the blood of lung cancer patients and has been regarded as a potential biomarker of lung cancer. It has a role as a biomarker. It is a saturated fatty aldehyde, a n-alkanal and a medium-chain fatty aldehyde.