Prognostic values of L-type amino acid transporter 1 and CD98hc expression in breast cancer

AIMS: L-type amino acid transporter 1 (LAT1) is a major Na(+)-independent neutral amino acid transporter, forming a complex with CD98hc. The aim of this study is to investigate the significance of LAT1 and CD98hc in invasive breast cancer. METHODS: LAT1 and CD98hc expression was immunohistochemically assessed in 280 invasive breast cancers and analysed for association with clinicopathological features. RESULTS: High levels of LAT1 and CD98hc were observed in triple-negative breast cancers (TNBCs) possessing negative immunoreactivity with oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, compared with non-TNBCs (NTNBCs), and were associated with lymph-node metastasis and higher nuclear grade. The high-LAT1-expression group showed a poor prognosis in NTNBC and TNBC, however, high-CD98hc-expression group showed a poor prognosis only in NTNBC. LAT1 and CD98hc expression could be the prognostic factors in univariate analyses, but not in multivariate analyses. Further, we found that invasive tumour components showed higher LAT1 and CD98hc expression than non-invasive tumour components. CONCLUSIONS: LAT1 and CD98hc may possess prognostic values in invasive breast cancer. LAT1 may be linked with cancer cell activities and disease progression in breast cancer.