Maybe marks tumor. Cea is a protein that can be made by some malignant tumor cells (cancer-ca). Some benign diseases can increase cea levels. High cea doesn't make a diagnosis. Helpful for follow up. If ca diagnosed, cea checked. If elevated, follow after treatment. So if cea high before surgery, cea should fall after, and with chemo/rt. Cea rises can be with recurrence or metastatic spread. Lower is better.