Gokden Neriman, Gokden Murat, Phan Dan C, McKenney Jesse K
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Am J Surg Pathol. 2008 Oct;32(10):1462-7. doi: 10.1097/PAS.0b013e318176dba7.
PAX-2 is a homeogene expressed during kidney development. Although immunohistochemical expression of PAX-2 has been described in a variety of primary renal cell carcinoma (RCC) subtypes and in metastatic RCC, its specificity as a marker of renal lineage in a metastatic setting has not been fully evaluated. In addition, its utility has not been directly compared with the most widely used antibody in this setting, renal cell carcinoma marker (RCCma). We studied PAX-2 expression in metastatic clear cell renal cell carcinoma (CC-RCC) and in a variety of nonrenal neoplasms with clear cytoplasm that may potentially mimic CC-RCC. Archival material from 27 CC-RCCs metastatic to various organs and 50 close morphologic mimics of CC-RCC were retrieved. Immunohistochemistry with PAX-2 and RCCmapi antibodies was performed on each case. Nuclear staining (PAX-2) or membranous staining (RCCma) was scored semiquantitatively. Twenty-three of 27 (85%) metastatic CC-RCCs showed nuclear immunoreactivity for PAX-2, whereas RCCma reactivity was found in 19 of 27 (70%). The immunoprofiles of the metastatic CC-RCC were PAX-2+/RCCma+: 19 of 27 (70%), PAX-2+/RCCma-: 5 of 27 (19%), PAX-2-/RCCma+: 2 of 27 (7%), and PAX-2-/RCCma-: 1 of 27 (4%). Five of the 50 mimics of CC-RCC (10%) had at least focal nuclear reactivity with PAX-2, including 1 of 3 parathyroid carcinomas (33%), 3 of 7 clear cell carcinomas of the ovary (43%), and the 1 clear cell papillary cystadenoma of the epididymis. Membranous RCCma reactivity was identified in 26 of the 50 mimics (52%). We conclude that PAX-2 is a useful marker for distinguishing metastatic CC-RCC from its potential morphologic mimics, but caution must be used in certain differential diagnostic settings where nonrenal tumors such as parathyroid carcinoma, ovarian clear cell carcinoma, and clear cell papillary cystadenoma of the epididymis were shown to express both PAX-2 and RCCma.
PAX-2是一种在肾脏发育过程中表达的同源基因。尽管PAX-2的免疫组化表达已在多种原发性肾细胞癌（RCC）亚型和转移性RCC中有所描述，但其作为转移情况下肾谱系标志物的特异性尚未得到充分评估。此外，其效用尚未与该情况下最广泛使用的抗体——肾细胞癌标志物（RCCma）进行直接比较。我们研究了PAX-2在转移性透明细胞肾细胞癌（CC-RCC）以及各种可能潜在模仿CC-RCC的具有透明细胞质的非肾肿瘤中的表达情况。检索了27例转移至各器官的CC-RCC以及50例形态学上与CC-RCC相似的病例的存档材料。对每个病例进行PAX-2和RCCmapi抗体的免疫组化检测。对核染色（PAX-2）或膜染色（RCCma）进行半定量评分。27例转移性CC-RCC中有23例（85%）显示PAX-2核免疫反应阳性，而27例中有19例（70%）发现RCCma反应阳性。转移性CC-RCC的免疫表型为PAX-2+/RCCma+：27例中有19例（70%），PAX-2+/RCCma-：27例中有5例（19%），PAX-2-/RCCma+：27例中有2例（7%），PAX-2-/RCCma-：27例中有1例（4%）。50例CC-RCC模仿病例中有5例（10%）至少有局灶性PAX-2核反应阳性，包括3例甲状旁腺癌中的1例（33%）、7例卵巢透明细胞癌中的3例（43%）以及1例附睾透明细胞乳头状囊腺瘤。50例模仿病例中有26例（52%）发现膜性RCCma反应阳性。我们得出结论，PAX-2是区分转移性CC-RCC与其潜在形态学模仿物的有用标志物，但在某些鉴别诊断情况下必须谨慎，因为甲状旁腺癌、卵巢透明细胞癌和附睾透明细胞乳头状囊腺瘤等非肾肿瘤显示同时表达PAX-2和RCCma。
