Hassanein A M, Glanz S M
Department of Pathology, University of Florida College of Medicine, Gainesville, FL, USA.
Br J Dermatol. 2004 Mar;150(3):511-6. doi: 10.1046/j.1365-2133.2004.05811.x.
Beta-catenin is a 92-kDa protein, initially identified as a coprecipitating species with the E-cadherin cell-cell adhesive complex. It plays a role in signal transduction in the Wnt signalling pathway and has been identified as an oncogene in colon cancer and melanoma. Exon 3 beta-catenin-activating mutations were found in 75% of cases of pilomatricoma (PM). Previous studies have shown that nuclear and/or cytoplasmic staining may correlate with beta-catenin gene mutation.
Because the immunohistochemical expression of beta-catenin in the nucleus or the cytoplasm correlates with beta-catenin mutation, we studied the immunohistochemical profile of beta-catenin expression in normal scalp hair follicles and in PM and pilomatrix carcinoma (PC).
We reviewed 21 cases of PM and five cases of PC using immunohistochemical staining with commercially available antibody in a standard fashion on formalin-fixed paraffin-embedded tissue samples.
All 26 tumours displayed both nuclear and cytoplasmic staining in the basaloid cells with focal membranous staining. Shadow cells were negative in all tumours. Normal control sections from the scalp displayed nuclear reactivity of the matrical cells, mostly concentrated in the supramatrical zone of hair follicles. Membranous staining was present along the intercellular junctions of the epidermis and along the outer and inner root sheaths of hair follicles. We have found similar patterns of beta-catenin nuclear and cytoplasmic expression in both PM and PC.
Despite the shared beta-catenin expression, the biological behaviour of PM and PC is markedly different. These two tumours probably share the activation of a common cellular pathway that could be related to their shared method of keratinization or a shared dysfunction of the cellular adhesion complex and consequently tumorigenesis. To the best of our knowledge, this is the first report on the beta-catenin immunohistochemical expression profile in PC.
β-连环蛋白是一种92 kDa的蛋白质，最初被鉴定为与E-钙黏蛋白细胞间黏附复合物共沉淀的物质。它在Wnt信号通路的信号转导中起作用，并已被确定为结肠癌和黑色素瘤中的一种癌基因。在75%的毛母质瘤（PM）病例中发现了外显子3 β-连环蛋白激活突变。先前的研究表明，细胞核和/或细胞质染色可能与β-连环蛋白基因突变相关。
由于β-连环蛋白在细胞核或细胞质中的免疫组化表达与β-连环蛋白突变相关，我们研究了β-连环蛋白在正常头皮毛囊、PM和毛母质癌（PC）中的免疫组化表达谱。
我们使用市售抗体，以标准方式对福尔马林固定石蜡包埋的组织样本进行免疫组化染色，回顾性分析了21例PM和5例PC。
所有26个肿瘤的基底样细胞均显示细胞核和细胞质染色，并伴有局灶性膜染色。所有肿瘤中的影子细胞均为阴性。头皮的正常对照切片显示母质细胞的细胞核反应性，主要集中在毛囊的母质上区。膜染色出现在表皮的细胞间连接处以及毛囊的外根鞘和内根鞘。我们在PM和PC中发现了相似的β-连环蛋白细胞核和细胞质表达模式。
尽管PM和PC有共同的β-连环蛋白表达，但它们的生物学行为明显不同。这两种肿瘤可能共享一条共同的细胞途径的激活，这可能与其共同的角质化方式或细胞黏附复合物的共同功能障碍以及随后的肿瘤发生有关。据我们所知，这是关于PC中β-连环蛋白免疫组化表达谱的首次报道。
