Sekine S, Takata T, Shibata T, Mori M, Morishita Y, Noguchi M, Uchida T, Kanai Y, Hirohashi S
Pathology Division, National Cancer Center Research Institute, Tokyo, Japan.
Histopathology. 2004 Dec;45(6):573-9. doi: 10.1111/j.1365-2559.2004.02029.x.
Adamantinomatous craniopharyngioma (ACP) resembles histologically some odontogenic tumours, such as ameloblastoma and calcifying odontogenic cyst. However, there has been no evidence that ACP differentiates also functionally as odontogenic epithelium. The aim of this study was to gain evidence of odontogenic epithelial differentiation in ACP by means of immunohistochemistry. Among normal human tissues, enamel proteins are expressed exclusively in teeth, and lymphoid enhancer factor 1 (LEF1), in co-operation with beta-catenin, play an important role in tooth development. The expression of these proteins is therefore indicative of odontogenic epithelial differentiation.
The expression of enamel proteins and LEF1 was examined in 10 adamantinomatous and six papillary craniopharyngiomas. All the ACPs showed a variable degree of enamel protein expression, including amelogenin, enamelin and enamelysin, mainly in ghost cells. LEF1 was also heterogeneously expressed in ACPs; remarkably, its expression pattern was identical to that of nuclear beta-catenin accumulation. In contrast, none of the papillary craniopharyngiomas expressed enamel proteins or LEF1.
These results suggest that ACP consistently shows odontogenic epithelial differentiation. Since ACPs harbour beta-catenin mutation, the inappropriate activation of beta-catenin/LEF1 complex-dependent transcription may play a critical role in ACP tumorigenesis.
成釉细胞瘤型颅咽管瘤（ACP）在组织学上类似于某些牙源性肿瘤，如成釉细胞瘤和牙源性钙化囊肿。然而，尚无证据表明ACP在功能上也能分化为牙源性上皮。本研究的目的是通过免疫组织化学方法获得ACP中牙源性上皮分化的证据。在正常人体组织中，釉质蛋白仅在牙齿中表达，而淋巴样增强因子1（LEF1）与β-连环蛋白协同作用，在牙齿发育中起重要作用。因此，这些蛋白的表达表明牙源性上皮分化。
检测了10例成釉细胞瘤型和6例乳头型颅咽管瘤中釉质蛋白和LEF1的表达。所有ACP均显示出不同程度的釉质蛋白表达，包括釉原蛋白、釉蛋白和釉质溶解蛋白，主要存在于影细胞中。LEF1在ACP中也呈异质性表达；值得注意的是，其表达模式与核β-连环蛋白积累的模式相同。相比之下，乳头型颅咽管瘤均未表达釉质蛋白或LEF1。
这些结果表明ACP始终表现出牙源性上皮分化。由于ACP存在β-连环蛋白突变，β-连环蛋白/LEF1复合物依赖性转录的不适当激活可能在ACP的肿瘤发生中起关键作用。
