Correlation of high LAT1 expression with the prognosis of endometrioid carcinoma of the uterine corpus.

The expression of L-type amino acid transporter 1 (LAT1) has been described to play essential roles in cancer cell growth and survival. To determine the significance of LAT1 in the prognosis of endometrial endometrioid carcinoma, we investigated LAT1 expression in 353 endometrioid carcinoma patients by immunohistochemical analysis using tissue microarray. The tumors in which stained tumor cells made up more than 25% of the tumor were graded as high expression. High expression of LAT1 was detected in 29 (8.2%) of patients. The ratio of high LAT1 expression did not significantly differ by age (< 60 vs. ≥ 60), FIGO stage (stage I/II vs. III/IV), histological grade (grade 1 vs. grade 2/3), or lymph node metastasis (positive vs. negative). However, high LAT1 expression in endometrioid carcinoma was associated with a poorer progression-free survival and overall survival, as per the results of the log-rank test (P = 0.0263 and 0.0404, respectively). Cox univariate and multivariate analyses revealed that high LAT1 expression is an independent marker of poor progression-free survival (hazard ratio = 2.598, P = 0.0137), in addition to a higher age (≥ 60 years vs. < 60 years), FIGO stage (stage III/IV vs. I/II), and histological grade (grade 2/3 vs. grade 1). In conclusion, we demonstrate that LAT1 is associated with a poor prognosis of endometrioid carcinoma of the uterine corpus.