Higher autumnal HCC are in agreement with the described pituitary gland circannual rhythm of the equine, which has the highest ACTH output in the fall [18,39,40,41], and the lowest spring HCC levels were consistent with the observations of Aurich et al. [11], who reported lower salivary cortisol levels in March and April when considering the period from December to May. This evidence concerns the gene POMC and hepatocellular carcinoma.