Serum ferritin is a commonly used clinical tumor marker. Its elevation is most commonly caused by the synthesis of ferritin by cancer cells in malignant tumors and its release into the blood, more commonly seen in hepatocellular carcinoma, but also in lung cancer, pancreatic cancer, colon cancer, prostate cancer, acute leukemia, etc. Besides malignant tumors, some benign diseases, such as acute and chronic hepatitis, cirrhosis, acute infection, chronic nephritis, nephrotic syndrome, chronic inflammation, pigmentation disorders, etc. can also cause elevated ferritin. Therefore, ferritin is only used as a screening indicator for malignant tumors, and it can also be used as an observation indicator for the efficacy of malignant tumors that have been diagnosed, but it cannot be used as a basis for the diagnosis of malignant tumors. If elevated serum ferritin is found, further imaging examinations should be performed, focusing on the liver, pancreas, lung, prostate and blood system to exclude malignant tumors in the corresponding areas.