The deficiency of the cysteine dioxygenase 1 (CDO1) expression has been reported in lung [1], endometrial [2], breast [3], prostate [4], clear-cell renal cell [5], and gastrointestinal [6] cancers to date, and this aberration correlates with poor survival outcomes in patients with the examined cancer types [4, 5, 7–10]. Here, CDO1 is linked to cancer.