Variations of Blood Concentration Levels of Reactive Carbonyl Species Among Three Case-Control Studies of Breast and Colorectal Cancer.

Oxidative stress is one of the major causes of cancer. Interactions with proteins and nucleic acids of lipid peroxidation-derived reactive carbonyl species (RCS), which act as secondary signaling intermediates and contribute to oxidative stress signals, are associated with cancer development. The aim of the present study was to identify novel biomarkers for the detection of a high-risk group and/or early disease diagnosis, and to elucidate the roles of RCS on the development of breast and colorectal cancers. In the present study, a comprehensive method was applied for analysis of RCS in plasma/serum samples from three case-control studies of colorectal and breast cancers. In a breast cancer study, RCS with average concentrations > 1000 pmol/mL showed higher levels of pentadecanal, tridecanal, and undecanal compared with controls. On the other hand, in a colorectal cancer study, lower octadecanal were observed, but higher RCS was not observed. Among RCS with average concentration levels of < 1000 pmol/mL, higher concentrations of cis-4-decenal were noted in colorectal and breast cancer studies, suggesting that they may be candidate biomarkers for high-risk groups and/or early diagnosis. Furthermore, variations of blood concentrations of RCS were noted among case-control studies of breast and colorectal cancer. Further studies are required to identify suitable and feasible sampling conditions, storage periods of blood samples, and additional candidates of biomarkers for the detection of high-risk groups and early diagnosis.