Co-expression effect of LLGL2 and SLC7A5 to predict prognosis in ERα-positive breast cancer
Tomoka Hisada, Naoto Kondo, Yumi Wanifuchi‐Endo, Satoshi Osaga, Takashi Fujita, Tomoko Asano, Yasuaki Uemoto, Sayaka Nishikawa, Yusuke Katagiri, Mitsuo Terada, Akiko Kato, Hiroshi Sugiura, Katsuhiro Okuda, Hiroyuki Kato, Masayuki Komura, Satoshi Morita, Satoru Takahashi, Tatsuya Toyama
Abstract
Abstract Lethal giant larvae homolog 2 (LLGL2) and solute carrier family 7 member 5 (SLC7A5) have been reported to be involved in resistance to endocrine therapy. This study aimed to assess the effects of LLGL2/SLC7A5 co-expression in predicting prognosis and response to tamoxifen therapy in ERα-positive breast cancer patients according to LLGL2/SLC7A5 mRNA and protein expression in long-term follow-up invasive breast cancer tissues. We identified that low LLGL2/SLC7A5 mRNA co-expression ( LLGL2 low / SLC7A5 low ) was associated with disease-free survival (DFS) compared with other combination groups in all breast cancer patients. In ERα-positive breast cancer patients, LLGL2 low / SLC7A5 low showed longer DFS and overall survival (OS) compared with LLGL2 high / SLC7A5 high and a positive trend of longer survival compared with the other combination groups. We also observed that LLGL2 low / SLC7A5 low showed longer survival compared with LLGL2 high / SLC7A5 high in ERα-positive breast cancer patients receiving adjuvant tamoxifen therapy. Multivariate analysis demonstrated that LLGL2 low / SLC7A5 low was an independent favorable prognostic factor of both DFS and OS, not only in all breast cancer patients, but also in ERα-positive breast cancer patients. High co-expression of LLGL2 and SLC7A5 protein showed a positive trend of shorter survival. Our study showed that co-expression of LLGL2 and SLC7A5 mRNA is a promising candidate biomarker in early breast cancer patients.