Kaira Kyoichi, Oriuchi Noboru, Imai Hisao, Shimizu Kimihiro, Yanagitani Noriko, Sunaga Noriaki, Hisada Takeshi, Ishizuka Tamotsu, Kanai Yoshikatsu, Endou Hitoshi, Nakajima Takashi, Mori Masatomo
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Showa-machi, Maebashi, Gunma 371-8511, Japan.
J Surg Oncol. 2009 Jun 1;99(7):433-8. doi: 10.1002/jso.21277.
L-type amino acid transporter 1 (LAT1) has been associated with tumor growth and is highly expressed in the primary human neoplasms. We investigated the significance of LAT1 expression to evaluate malignant potential in thymic epithelial tumors.
Immunohistochemical studies of 45 surgically resected thymic epithelial tumors [15 noninvasive thymomas (NT), 22 invasive thymomas (IT), and 8 thymic carcinomas (TC)] were conducted. LAT1, Ki-67 labeling index (LI), vascular endothelial growth factor (VEGF), and microvessel density of the thymic epithelial tumors were analyzed.
LAT1 expression for thymomas and thymic carcinomas were 0 (0%) of 37 and 6 (75%) of eight patients, respectively. Ki-67 LI for NT, IT, and TC were 7.9 +/- 2.8%, 16.1 +/- 8.5%, and 50.6 +/- 24.4%, respectively. VEGF expression in groups NT, IT, and TC was 0 (0%) of 15, 9 (41%) of 22, and 6 (75%) of eight patients, respectively. VEGF expression was statistically associated with microvessel count. The LAT1 expression was statistically associated with Ki-67 LI, VEGF, and microvessel density in thymic carcinomas.
LAT1 is frequently expressed in thymic carcinomas but is absent in thymomas. Our results suggest that LAT1 expression might be an immunohistochemical marker for carcinomas, and could distinguish between thymomas and thymic carcinomas.
L型氨基酸转运体1（LAT1）与肿瘤生长相关，且在原发性人类肿瘤中高表达。我们研究了LAT1表达在评估胸腺上皮肿瘤恶性潜能中的意义。
对45例手术切除的胸腺上皮肿瘤[15例非侵袭性胸腺瘤（NT）、22例侵袭性胸腺瘤（IT）和8例胸腺癌（TC）]进行免疫组织化学研究。分析胸腺上皮肿瘤的LAT1、Ki-67标记指数（LI）、血管内皮生长因子（VEGF）和微血管密度。
胸腺瘤和胸腺癌患者的LAT1表达分别为37例中的0例（0%）和8例中的6例（75%）。NT、IT和TC的Ki-67 LI分别为7.9±2.8%、16.1±8.5%和50.6±24.4%。NT、IT和TC组中VEGF表达分别为15例中的0例（0%）、22例中的9例（41%）和8例中的6例（75%）。VEGF表达与微血管计数在统计学上相关。胸腺癌中LAT1表达与Ki-67 LI、VEGF和微血管密度在统计学上相关。
LAT1在胸腺癌中频繁表达，但在胸腺瘤中不存在。我们的结果表明，LAT1表达可能是癌的免疫组织化学标志物，并且可以区分胸腺瘤和胸腺癌。
