Prognostic significance of amino-acid transporter expression (LAT1, ASCT2, and xCT) in surgically resected tongue cancer

外科的に切除した舌癌におけるアミノ酸トランスポーター(LAT1, ASCT2, xCT)発現の治療予後における重要性

豊田 実*; 解良 恭一*; 大島 康宏; 石岡 典子; 紫野 正人*; 坂倉 浩一*; 高安 幸弘*; 高橋 克昌*; 富永 英之*; 織内 昇*; 永森 收志*; 金井 好克*; 小山 徹也*; 近松 一朗*

Toyoda, Minoru*; Kaira, Kyoichi*; Ohshima, Yasuhiro; Ishioka, Noriko; Shino, Masato*; Sakakura, Koichi*; Takayasu, Yukihiro*; Takahashi, Katsumasa*; Tominaga, Hideyuki*; Oriuchi, Noboru*; Nagamori, Shushi*; Kanai, Yoshikatsu*; Oyama, Tetsunari*; Chikamatsu, Kazuaki*

Amino-acid transporters are necessary for the tumor cell growth and survival, and play a crucial role in the development of cancer. But, it remains unclear about the prognostic significance of L-type amino acid transporter 1 (LAT1), System ASC amino acid transporter 2 (ASCT2) and xCT expression in patients with tongue cancer. We conducted the clinicopathological study to investigate the protein expression of these amino acid transporters in tongue cancer. Eighty-five patients with surgically resected tongue cancer were evaluated. Tumor sections were stained by immunohistochemistry for LAT1, ASCT2, xCT, CD98, Ki-67, CD34 and p53. The expression of LAT1 and ASCT2 was significantly associated with disease staging, lymph node metastasis, lymphatic permeation, vascular invasion, CD98 expression and cell proliferation (Ki-67). xCT expression indicated a significant association with advanced stage and tumor factor, correlated with CD98. By univariate analysis, both LAT1 and ASCT2 had a significant relationship with prognosis. Multivariate analysis confirmed that LAT1 were independent prognostic factors for predicting poor prognosis. These results suggest that LAT1 and ASCT2 can serve as a significant prognostic factor for predicting worse outcome after surgical treatment and may play an important role in the development and pathogenesis for tongue cancer.