Kuroda N, Inoue K, Guo L, Miyazaki E, Hayashi Y, Naruse K, Toi M, Hiroi M, Shuin T, Enzan H
First Department of Pathology, Kochi Medical School, Kochi, Japan.
Hum Pathol. 2001 Oct;32(10):1071-7. doi: 10.1053/hupa.2001.28235.
CD9 is a glycoprotein that is abundant in hematopoietic cells. Recently, it has been reported that CD9 is also present in the human kidney. In this article, we investigated the expression of CD9 using an immunohistochemical technique. We also studied the expression of CD9 protein and messenger RNA (mRNA) in tissue samples of some renal tumors using immunoblotting and reverse-transcription polymerase chain reaction (RT-PCR) analysis. Immunohistochemically, all tumors of papillary and chromophobe renal cell carcinomas (RCCs) and oncocytomas expressed CD9. In addition, CD9 was expressed in 31 of 66 conventional RCCs and 1 of 4 collecting duct carcinomas. On immunoelectron microscopy, CD9 was identified on the plasma membrane of a conventional RCC. The presence of CD9 protein in normal kidneys and various renal tumors, except for a collecting duct carcinoma and an oncocytoma, was confirmed by immunoblotting. On RT-PCR analysis, the expression of CD9 mRNA was observed in 1 normal kidney, 2 conventional RCCs, and 1 oncocytoma. The frequency of immunohistochemical CD9 positivity was significantly higher in papillary and chromophobe RCCs than in collecting duct carcinomas and conventional RCCs, respectively. These results suggest that CD9 may be a beneficial marker in the differential diagnosis between papillary RCCs and collecting duct carcinomas and also between chromophobe and conventional RCCs.
CD9是一种在造血细胞中大量存在的糖蛋白。最近，有报道称CD9也存在于人类肾脏中。在本文中，我们使用免疫组织化学技术研究了CD9的表达情况。我们还通过免疫印迹和逆转录聚合酶链反应（RT-PCR）分析，研究了一些肾肿瘤组织样本中CD9蛋白和信使核糖核酸（mRNA）的表达情况。免疫组织化学结果显示，所有乳头状和嫌色性肾细胞癌（RCC）以及嗜酸细胞瘤均表达CD9。此外，66例传统型RCC中有31例以及4例集合管癌中有1例表达CD9。免疫电子显微镜检查发现，在一例传统型RCC的质膜上可识别出CD9。免疫印迹证实，除集合管癌和嗜酸细胞瘤外，正常肾脏和各种肾肿瘤中均存在CD9蛋白。RT-PCR分析显示，在1例正常肾脏、2例传统型RCC和1例嗜酸细胞瘤中观察到了CD9 mRNA的表达。免疫组织化学检测中，CD9阳性的频率在乳头状和嫌色性RCC中分别显著高于集合管癌和传统型RCC。这些结果表明，CD9可能是乳头状RCC与集合管癌以及嫌色性与传统型RCC鉴别诊断中的一个有益标志物。
