Xiao Guang-Qian, Unger Pamela D, Burstein David E
Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Ann Diagn Pathol. 2007 Aug;11(4):235-40. doi: 10.1016/j.anndiagpath.2006.06.010.
The X-linked inhibitor of apoptosis (XIAP) is the most potent of the inhibitors of apoptosis, a group of related caspase inhibitors. X-linked inhibitor of apoptosis expression correlates with radio- and chemoresistance and clinical aggressiveness in certain tumors. XIAP expression was examined in 106 specimens from neoplastic and other thyroid disorders, which underwent citrate-based antigen retrieval and staining with monoclonal anti-XIAP. Normal thyroid was XIAP-negative. Of 35 papillary thyroid carcinomas (PTCs), 29 (83%) stained variably in intensity and/or extent. An insular carcinoma was strongly positive and 1 of 4 anaplastic carcinomas moderately positive. Follicular, medullary, and 3 of 4 anaplastic carcinomas, oncocytic neoplasms, and a hyalinizing trabecular tumor were nonstaining. Hashimoto's thyroiditis and adenomatous goiters were either nonstaining or occasionally stained in oncocytic foci. Because XIAP was highly specific for PTC among the thyroid neoplasms, it may be a useful marker for differential diagnosis when used alone or in combination with other markers. XIAP may also be useful in differentiating insular carcinoma from follicular neoplasm in certain difficult cases. In addition, the selective expression of XIAP in PTC and some high-grade thyroid malignancies also provides clues to the role of the apoptotic pathway in the tumorigenesis of these neoplasms.
X连锁凋亡抑制蛋白（XIAP）是凋亡抑制蛋白中最具活性的一种，凋亡抑制蛋白是一组相关的半胱天冬酶抑制剂。X连锁凋亡抑制蛋白的表达与某些肿瘤的放射抗性、化学抗性及临床侵袭性相关。对106例取自肿瘤性及其他甲状腺疾病的标本进行了X连锁凋亡抑制蛋白表达检测，这些标本经柠檬酸盐抗原修复处理后，用抗X连锁凋亡抑制蛋白单克隆抗体进行染色。正常甲状腺组织X连锁凋亡抑制蛋白呈阴性。在35例乳头状甲状腺癌（PTC）中，29例（83%）染色强度和/或范围各异。1例岛状癌呈强阳性，4例间变性癌中有1例呈中度阳性。滤泡状癌、髓样癌、4例间变性癌中的3例、嗜酸性细胞瘤及1例透明变小梁状肿瘤均未染色。桥本甲状腺炎和腺瘤性甲状腺肿未染色或仅在嗜酸性细胞灶偶尔染色。由于X连锁凋亡抑制蛋白在甲状腺肿瘤中对乳头状甲状腺癌具有高度特异性，单独使用或与其他标志物联合使用时，它可能是一种有用的鉴别诊断标志物。在某些疑难病例中，X连锁凋亡抑制蛋白在鉴别岛状癌和滤泡状肿瘤方面可能也有用。此外，X连锁凋亡抑制蛋白在乳头状甲状腺癌和一些高级别甲状腺恶性肿瘤中的选择性表达，也为凋亡途径在这些肿瘤发生中的作用提供了线索。
