Busam K J, Chen Y T, Old L J, Stockert E, Iversen K, Coplan K A, Rosai J, Barnhill R L, Jungbluth A A
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Am J Surg Pathol. 1998 Aug;22(8):976-82. doi: 10.1097/00000478-199808000-00007.
The Melan-A (MART1) gene encodes an antigen recognized by cytotoxic T cells. Although its expression in metastatic melanoma has been documented in the literature by several investigators, little is known about its distribution in primary melanomas and benign melanocytic nevi. In this study, we evaluated Melan-A expression immunohistochemically on sections from paraffin-embedded material of 50 benign nevi and 40 primary cutaneous melanomas using the monoclonal antibody A103. To evaluate a potential role of A103 in the differential diagnosis of melanocytic from nonmelanocytic tumors, we also analyzed a number of benign and malignant peripheral nerve sheath tumors, fibrohistiocytic tumors, and leiomyosarcomas. Immunoreactivity with A103 was present in all "nonneurotized" nevi and in all nondesmoplastic primary melanomas, both in the intraepidermal and the dermal component. Only two nevi that underwent prominent neurotization showed no staining with A103. Although all melanomas with epithelioid cells tended to be strongly positive with A103, only 4 of 13 spindle cell and desmoplastic melanomas (all positive with anti-S-100 and negative with HMB-45) were immunoreactive with A103 (two focally, two diffusely). None of the nonmelanocytic lesions expressed Melan-A. Our results confirm that Melan-A protein is broadly expressed in the majority of benign and malignant melanocytic lesions and suggest that A103 can be helpful diagnostically, not only for metastatic tumors, but also for primary skin lesions. Its use in distinguishing between melanocytic and peripheral nerve sheath tumors, however, is limited because of the low or absent expression of Melan-A in nevi that underwent neurotization and spindle cell and desmoplastic melanomas.
黑色素A（MART1）基因编码一种可被细胞毒性T细胞识别的抗原。尽管已有数名研究者在文献中记载了其在转移性黑色素瘤中的表达情况，但对于其在原发性黑色素瘤和良性黑素细胞痣中的分布却知之甚少。在本研究中，我们使用单克隆抗体A103，通过免疫组织化学方法对50例良性痣和40例原发性皮肤黑色素瘤石蜡包埋材料切片中的黑色素A表达进行了评估。为了评估A103在黑素细胞性肿瘤与非黑素细胞性肿瘤鉴别诊断中的潜在作用，我们还分析了一些良性和恶性外周神经鞘瘤、纤维组织细胞瘤和平滑肌肉瘤。A103免疫反应性存在于所有“非神经化”痣以及所有非促纤维增生性原发性黑色素瘤的表皮内和真皮成分中。仅2例发生显著神经化的痣未显示A103染色。尽管所有具有上皮样细胞的黑色素瘤往往对A103呈强阳性，但13例梭形细胞和促纤维增生性黑色素瘤（均对抗S-100呈阳性且对HMB-45呈阴性）中只有4例对A103呈免疫反应性（2例局灶性，2例弥漫性）。所有非黑素细胞性病变均未表达黑色素A。我们的结果证实黑色素A蛋白在大多数良性和恶性黑素细胞性病变中广泛表达，并表明A103不仅对转移性肿瘤，而且对原发性皮肤病变的诊断可能有帮助。然而，由于在发生神经化的痣以及梭形细胞和促纤维增生性黑色素瘤中黑色素A表达低或无表达，其在区分黑素细胞性肿瘤与外周神经鞘瘤方面的应用有限。
