Ferritin >400μg/L is not necessarily cancer. There are many reasons for elevated ferritin, besides cancer, inflammation, excessive blood transfusion and iron overload can all cause elevated ferritin, so elevated ferritin >400μg/L is not necessarily cancer. Cancer diagnosis requires tumor marker examination. Pathological tumor marker is only a reference aspect, no matter how elevated it is, it cannot diagnose cancer, but can only serve as a hint for diagnosis, cancer diagnosis must be confirmed by finding cancer cells in tissues. Serum ferritin is only one of the tumor markers, or one of the inflammation markers, and is not a decisive diagnostic indicator of cancer. Therefore, ferritin >400μg/L does not necessarily mean cancer, and further examination of the cause of elevation is needed.