Bologna-Molina R, Mikami T, Pereira-Prado V, Pires F-R, Carlos-Bregni R, Mosqueda-Taylor A
Health Care Department, Universidad Autónoma Metropolitana Xochimilco, Calzada del Hueso 1100, Villa Quietud, Mexico City 04960,
Med Oral Patol Oral Cir Bucal. 2017 May 1;22(3):e314-e323. doi: 10.4317/medoral.21859.
Primordial Odontogenic Tumor (POT) is a recently described odontogenic tumor characterized by a variably cellular loose fibrous tissue with areas similar to the dental papilla, covered by cuboidal to columnar epithelium that resembles the internal epithelium of the enamel organ, surrounded at least partly by a delicate fibrous capsule. The purpose of this study was to investigate the possible histogenesis and biological behavior of this rare tumor by means of a wide immunohistochemical analysis of its epithelial and mesenchymal components.
The immunoexpression of twenty-three different antibodies were evaluated in four cases of POT.
The epithelial cells that cover the periphery of the tumor showed immunopositivity for Cytokeratins 14 and 19, while Amelogenin, Glut-1, MOC-31, Caveolin-1. Galectin-3, PITX2, p53, Bax, Bcl-2, Survivin and PTEN were variably expressed in focal areas. The mesenchymal component of the tumor was positive for Vimentin, Syndecan-1, PITX2, Endoglin (CD105), CD 34, Cyclin D1, Bax, Bcl-2, Survivin and p53. PTEN and CD 90 showed a moderate positivity. BRAF V600E and Calretinin were negative in all samples. Cell proliferation markers (Ki-67, MCM-7) were expressed in <5% of the tumor cells.
According to these immunohistochemical findings, we may conclude that POT is a benign odontogenic tumor in which there is both epithelial and mesenchymal activity during its histogenesis, as there is expression of certain components in particular zones in both tissues that suggests this tumor develops during the immature (primordial) stage of tooth development, leading to its inclusion within the group of benign mixed epithelial and mesenchymal odontogenic tumours in the current World Health Organization classification of these lesions.
原始牙源性肿瘤（POT）是一种最近描述的牙源性肿瘤，其特征是具有不同细胞密度的疏松纤维组织，有类似于牙乳头的区域，表面覆盖着立方形至柱状上皮，类似于成釉器的内釉上皮，至少部分被一层薄的纤维包膜所包围。本研究的目的是通过对该罕见肿瘤的上皮和间充质成分进行广泛的免疫组织化学分析，探讨其可能的组织发生和生物学行为。
对4例POT病例评估了23种不同抗体的免疫表达情况。
覆盖肿瘤周边的上皮细胞对细胞角蛋白14和19呈免疫阳性，而釉原蛋白、葡萄糖转运蛋白1、MOC-31、小窝蛋白-1、半乳糖凝集素-3、PITX2、p53、Bax、Bcl-2、生存素和PTEN在局部区域呈不同程度表达。肿瘤的间充质成分对波形蛋白、多配体蛋白聚糖-1、PITX2、内皮糖蛋白（CD105）、CD 34、细胞周期蛋白D1、Bax、Bcl-2、生存素和p53呈阳性。PTEN和CD 90呈中度阳性。BRAF V600E和钙视网膜蛋白在所有样本中均为阴性。细胞增殖标志物（Ki-67、微小染色体维持蛋白7）在<5%的肿瘤细胞中表达。
根据这些免疫组织化学结果，我们可以得出结论，POT是一种良性牙源性肿瘤，在其组织发生过程中存在上皮和间充质活性，因为在两种组织的特定区域都有某些成分的表达，这表明该肿瘤在牙齿发育的不成熟（原始）阶段发生，从而使其被纳入世界卫生组织当前对这些病变的良性上皮和间充质混合性牙源性肿瘤分类中。
