[A rapid method for determining urinary indoleacetic acid concentration and its clinical significance as the tumor-marker in the diagnosis of malignant diseases].

A rapid method for determining urinary indole-3-acetic acid (IAA) is introduced as the tumor-marker for the screening and diagnostic purpose of cancer patients by means of high performance liquid chromatography (HPLC). Its clinical significance is discussed along with a review of literatures. The IAA concentration and creatinine level of optionally collected urine samples were measured and used for the calculation of IAA amount per unit creatinine (microgram IAA/mg creatinine) in urine. Thus, an amount of 24-hours urinary IAA could be calculated without collecting a whole day's urine supply. Analysis of urinary IAA was performed within 10 minutes by HPLC. Urinary IAA level is usually high in the patients with the upper G-I tract cancers such as gastric cancer, esophageal cancer and hepato-biliary tract cancer, and also malignant hematopoietic disorders. But it is also high in non-cancer patients such as liver cirrhosis, diabetes mellitus and cholelithiasis occasionally. The patients with high urinary IAA level also showed high urinary levels of 5-hydroxy indoleacetic acid (5-HIAA) and monoamine oxidase activity (MAO). It was characteristic that hepatocellular carcinoma showed slight elevation of urinary IAA with normal levels of 5-HIAA and MAO. It is conclusive that the positive rate of elevated urinary IAA level was high in the patients with gastric cancer with ulcer-forming type in its morphological classification, and its level tends to elevate as the disease progresses. Therefore, the measurement of urinary IAA level in an optionally collected urine sample, as the tumor-marker, can be useful to check the progression and regression of gastric cancer.