Akai Aki, Yamamura Yukie, Nonaka Manabu, Yoshihara Toshio
Department of Otolaryngology, Tokyo Women's Medical University, 8-1 Kawada cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Department of Otolaryngology, Tokyo Women's Medical University, 8-1 Kawada cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Auris Nasus Larynx. 2014 Dec;41(6):532-8. doi: 10.1016/j.anl.2014.08.002. Epub 2014 Sep 8.
Warthin's tumors and oncocytomas show exceptionally good (99m)TcO4(-) (Tc) accumulation images in Tc scintigraphy. However, the mechanism of Tc accumulation in these tumors remains unclear. Sodium-iodide symporter (NIS) is a plasma membrane protein expressed in the thyroid, lactating breast, stomach and salivary glands; it facilitates uptake of I(-) and Tc. We hypothesized that Warthin's tumor cells and oncocytomas may also express NIS, which would promote uptake of Tc. We examined NIS localization and the mechanism of Tc accumulation in various salivary gland tissues.
Immunohistological localization of NIS was performed for 19 tumors from 18 patients who underwent preoperative Tc scintigraphy. Expression of mRNA for NIS in the normal salivary gland, Warthin's tumors and pleomorphic adenomas was analyzed by real-time PCR.
In normal salivary glands, striated duct cells were strongly immunostained by anti-NIS antibodies. In Warthin's tumors, eosinophilic epithelial cells exhibited positive immunostaining, but their staining was varied among the cases. Furthermore, all Tc-positive specimens were NIS-positive, and all Tc-negative specimens were NIS-negative. Real-time PCR showed that NIS mRNA expression was detectable in normal salivary glands and Warthin's tumor cells. The expression was significantly higher in normal salivary glands compared with Warthin's tumor cells and pleomorphic adenoma.
Tc-positive salivary glands expressed NIS. Our findings suggest that Tc accumulation in Warthin's tumors and oncocytomas is due to poorer Tc excretory function compared with normal salivary gland tissues, in addition to active uptake of (99m)TcO4(-) via NIS.
沃辛瘤和嗜酸细胞瘤在锝（Tc）闪烁扫描中显示出异常良好的高锝酸盐（99mTcO4(-)，Tc）摄取图像。然而，这些肿瘤中Tc摄取的机制仍不清楚。钠-碘同向转运体（NIS）是一种在甲状腺、哺乳期乳腺、胃和唾液腺中表达的质膜蛋白；它促进碘离子（I(-)）和Tc的摄取。我们推测沃辛瘤细胞和嗜酸细胞瘤可能也表达NIS，这会促进Tc的摄取。我们研究了NIS在各种唾液腺组织中的定位以及Tc摄取的机制。
对18例术前行Tc闪烁扫描的患者的19个肿瘤进行NIS的免疫组织学定位。通过实时聚合酶链反应（PCR）分析正常唾液腺、沃辛瘤和多形性腺瘤中NIS的信使核糖核酸（mRNA）表达。
在正常唾液腺中，纹状管细胞被抗NIS抗体强烈免疫染色。在沃辛瘤中，嗜酸性上皮细胞呈现阳性免疫染色，但不同病例之间染色情况有所不同。此外，所有Tc阳性标本均为NIS阳性，所有Tc阴性标本均为NIS阴性。实时PCR显示，在正常唾液腺和沃辛瘤细胞中可检测到NIS mRNA表达。与沃辛瘤细胞和多形性腺瘤相比，正常唾液腺中的表达明显更高。
Tc阳性唾液腺表达NIS。我们的研究结果表明，除了通过NIS主动摄取99mTcO4(-)外，沃辛瘤和嗜酸细胞瘤中Tc的积聚是由于与正常唾液腺组织相比Tc排泄功能较差。
