I would like to agree, in general, with the view of Drs. Al-Shraim and Asa on the new WHO classification, especially on the necessity of introducing cell lineage. The basic tone of the argument for the new WHO histological classification of pituitary tumors was to try to build a new framework by shifting from the classical classification, which has been mainly based on electron microscopy, to a classification based on light microscopic immunohistochemistry. This was addressed on the background of recently accumulating knowledge on cell lineage of adenohypophysial cells. Nobody doubts that electron microscopic observations can provide essential information about cell nature, although it has been argued that electron microscopy has not been well performed even in sophisticated institutes. That is why each tumor type is primarily described on the basis of immunohistochemical information, such as growth hormone (GH)-producing adenoma, adrenocorticotropic hormone (ACTH)-producing adenoma, and so on. In my view, it seems to be indispensable to show a list of the WHO histological classification of pituitary tumors at the beginning of the chapter. Although a simple list of the WHO classification including typical adenoma, atypical adenoma and carcinoma is shown, it is not sufficient. In other chapters such as those on tumors of thyroid gland, adrenal gland and endocrine pancreas, the comprehensive list is appropriately documented with international classification of diseases (ICD) codes. Remarkably, glucagonoma and VIPoma of the endocrine pancreas, which are much rarer than GH-producing adenoma and ACTH-producing adenoma, are shown in a list with ICD codes. Table 1 may represent such a list of the new classification of pituitary tumors. I am afraid that people may misunderstand that Table 1.01, which shows the incidence of pituitary adenoma types classified by Horvath and Kovacs, indicates the new WHO classification, since this is the only list of pituitary adenoma types shown in the chapter.