Todo T, Buchfelder M, Thierauf P, Fahlbusch R
Department of Neurosurgery, University of Erlangen-Nürnberg, Germany.
Neurosurgery. 1993 Apr;32(4):635-42. doi: 10.1227/00006123-199304000-00022.
Immunohistochemical expression of the three major isozymes of protein kinase C--Types I, II, and III--was studied in 32 cases of human pituitary adenomas, and the results were compared in detail with their clinical data. Immunoreactivity for the Type I and Type II isozymes was negative in tumor cells of all pituitary adenomas. Moderate to strong cytoplasmic immunoreactivity for the Type III isozyme was constantly seen in acromegaly, Cushing's disease, and nonfunctioning adenomas, which indicated overexpression of the isozyme, since only slight cytoplasmic immunoreactivity was observed in the normal human anterior pituitary cells. Among 13 prolactinomas, 5 cases showed positive immunoreactivity for Type III in all tumor cells, whereas 8 cases showed negative immunoreactivity for the isozyme in all or more than 85% of tumor cells. The sizes of the tumors in this protein kinase C Type III negative group of prolactinomas tended to be smaller than those of the Type III positive prolactinomas. Also, the negative immunoreactivity for Type III was predominantly observed in those cases where prolactinomas were relatively well controlled by continuous oral dosage of dopamine agonists before operation. These results suggest that protein kinase C Type III is closely involved in human pituitary adenomas. The exceptional negativity for the isozyme in prolactinomas may be relevant to the suppression of tumor growth by dopamine agonists.
研究了32例人垂体腺瘤中蛋白激酶C的三种主要同工酶——I型、II型和III型的免疫组化表达，并将结果与它们的临床数据进行了详细比较。所有垂体腺瘤的肿瘤细胞中I型和II型同工酶的免疫反应均为阴性。在肢端肥大症、库欣病和无功能腺瘤中，经常可见III型同工酶有中度至强的细胞质免疫反应，这表明该同工酶过度表达，因为在正常人垂体前叶细胞中仅观察到轻微的细胞质免疫反应。在13例催乳素瘤中，5例在所有肿瘤细胞中III型免疫反应呈阳性，而8例在所有或超过85%的肿瘤细胞中该同工酶免疫反应呈阴性。催乳素瘤的蛋白激酶C III型阴性组中的肿瘤大小往往比III型阳性催乳素瘤的肿瘤小。此外，III型免疫反应阴性主要见于术前通过持续口服多巴胺激动剂使催乳素瘤得到相对良好控制的病例。这些结果表明蛋白激酶C III型与人类垂体腺瘤密切相关。催乳素瘤中该同工酶的异常阴性可能与多巴胺激动剂对肿瘤生长的抑制作用有关。
