University of Helsinki, Helsinki, Finland.
Vet Pathol. 2022 Mar;59(2):236-243. doi: 10.1177/03009858211062636. Epub 2021 Dec 12.
Mast cell tumors (MCTs) are one of the most common cutaneous malignancies in dogs. Previous studies have reported expression of mast cell-specific proteases chymase and tryptase in canine cutaneous MCTs and in connective tissue and mucosal mast cells. In humans and rodents, mast cells express an additional specific protease, carboxypeptidase A3 (CPA3). In this article, we describe CPA3 immunoreactivity in connective tissue, visceral, mucosal, and neoplastic mast cells in dogs. Positive immunolabeling for CPA3 was observed in nonneoplastic mast cells in 20/20 formalin-fixed paraffin-embedded normal tissues (skin, liver, spleen, intestine), and in 63/63 MCTs irrespective of their histological grade. CPA3 protein expression was comparable to that of c-kit in both the nonneoplastic and neoplastic mast cells. Three distinct labeling patterns (membranous, diffuse, and focal cytoplasmic) were observed for CPA3 in MCTs. The focal cytoplasmic labeling pattern was associated with high-grade MCTs staged with the Kiupel 2-tier grading criteria. We propose CPA3 as a novel immunohistochemical marker for canine mast cells in health and disease.
肥大细胞瘤（MCT）是犬最常见的皮肤恶性肿瘤之一。先前的研究报告称，犬皮肤 MCT 中的结缔组织和黏膜肥大细胞以及组织特异性蛋白酶糜酶和类胰蛋白酶的表达。在人类和啮齿动物中，肥大细胞表达另一种特异性蛋白酶，羧肽酶 A3（CPA3）。在本文中，我们描述了犬结缔组织、内脏、黏膜和肿瘤肥大细胞中 CPA3 的免疫反应性。在 20/20 福尔马林固定石蜡包埋的正常组织（皮肤、肝脏、脾脏、肠道）的非肿瘤肥大细胞和 63/63 例 MCT 中观察到 CPA3 的阳性免疫标记，无论其组织学分级如何。CPA3 蛋白表达在非肿瘤和肿瘤肥大细胞中与 c-kit 相当。在 MCT 中观察到 CPA3 存在三种不同的标记模式（膜性、弥漫性和局灶性细胞质）。局灶性细胞质标记模式与 Kiupel 2 级分级标准中分级的高级别 MCT 相关。我们提出 CPA3 作为一种新的用于健康和疾病犬肥大细胞的免疫组织化学标志物。
