Abdelsayed Rafik A, Vartanian Robert K, Smith Kimberly K, Ibrahim Nabil A
Department of Oral Biology adn Maxillofacial Pathology, School of Dentistry, Medical College of Georgia, Augusta, 30912, USA.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004 Feb;97(2):208-19. doi: 10.1016/j.tripleo.2003.10.003.
Parathyroid hormone-related protein (PTHrP) production has been demonstrated in a variety of tumor subtypes. Local production of PTHrP by metastatic tumor cells in bone has been linked to bone destruction and tumor growth. Ameloblastoma (AB) is a relatively common odontogenic epithelial neoplasm that manifests local infiltrative intraosseous growth. AB recapitulates the developing enamel epithelium, in which PTHrP recently has been demonstrated. Yet PTHrP expression in a series of ABs has not been studied to date. The purpose of this investigation is to assess the expression of PTHrP in ameloblastoma.
Formalin-fixed, paraffin-embedded tissue sections of ameloblastoma (n = 30; 24 conventional, 4 unicystic, and 2 arising in dentigerous cyst) were immunostained with anti-PTHrP antibody using a multistep streptavidin-peroxidase technique. Semiquantitative scoring of immunoreactivity was assessed as mild, moderate, and intense.
All cases (100%) demonstrated positive immunoreactivity, with mild reaction in 3 conventional ABs, 1 unicystic and 1 AB arising in dentigerous cyst, and with moderate reaction in 12 conventional ABs, 3 unicystic and 1 AB arising in dentigerous cyst. Intense immunoreactivity was seen in 9 cases of conventional AB. This difference in immunostaining was not statistically significant (Sigma2 = 4.41, df = 4, P = .358).
The results of this investigation suggest that PTHrP may play a significant role in local bone resorption, offering at least partial explanation for the tumor's infiltrative growth and destructive behavior. The uniformity of PTHrP expression by AB, as detailed in this study, may harbor significant therapeutic implications, particularly through PTHrP-blocking treatment modalities.
已证实在多种肿瘤亚型中可产生甲状旁腺激素相关蛋白（PTHrP）。骨转移瘤细胞局部产生PTHrP与骨破坏和肿瘤生长有关。成釉细胞瘤（AB）是一种相对常见的牙源性上皮性肿瘤，表现为局部浸润性骨内生长。AB重现了发育中的釉质上皮，最近已证实在其中有PTHrP。然而，迄今为止尚未对一系列成釉细胞瘤中的PTHrP表达进行研究。本研究的目的是评估PTHrP在成釉细胞瘤中的表达。
采用多步链霉亲和素 - 过氧化物酶技术，用抗PTHrP抗体对成釉细胞瘤（n = 30；24例传统型、4例单囊性、2例发生于含牙囊肿）的福尔马林固定、石蜡包埋组织切片进行免疫染色。免疫反应性的半定量评分分为轻度、中度和重度。
所有病例（100%）均表现出阳性免疫反应性，3例传统型AB、1例单囊性和成釉细胞瘤发生于含牙囊肿中的1例呈轻度反应，12例传统型AB、3例单囊性和成釉细胞瘤发生于含牙囊肿中的1例呈中度反应。9例传统型AB可见强免疫反应性。这种免疫染色差异无统计学意义（Sigma2 = 4.41，自由度 = 4，P = 0.358）。
本研究结果表明，PTHrP可能在局部骨吸收中起重要作用，这至少部分解释了肿瘤的浸润性生长和破坏性行为。本研究详细阐述的成釉细胞瘤PTHrP表达的一致性可能具有重要的治疗意义，特别是通过PTHrP阻断治疗方式。
