The potential of AGP glycans expected as a novel tumor marker was further clarified by the following comprehensive analysis of AGP glycan structures in various cancer patients, in which a new MALDI-TOF-MS system was developed including a simple purification method of AGP and a rapid determination of primary structures of AGP glycans with the aid of the home-made software, AGPAS [22]. This evidence concerns the gene ATP5MK and neoplasm.