Alteration of circadian variation in serum concentrations of carcino-embryonic antigen (CEA) in cancer.

Abstract Evidence of circadian variation of CEA levels was provided in a non-cancer population. At a group level, cancer was characterized by the disappearance of “normal” fluctuations of CEA. At an individual level, part of the cancer patients retained circadian variability of CEA, but with different amplitudes and acrophases that reference group.