Background: The novel sugar transporter and membrane protein SLC50A1 has been identified as a potential candidate biomarker for breast cancer; however, its potential as a serum biomarker for breast cancer detection and prognosis is unclear. The aim of this study was to investigate the serum expression profile of SLC50A1 and to determine its diagnostic and prognostic significance in breast cancer.
Materials and methods: Bioinformatics analysis was conducted, and data for SLC50A1  expression in human breast cancer were collected. Semi-quantitative real-time PCR and ELISA were performed to compare SLC50A1 expression in several breast cancer cell lines, one paired tissue cohort (n=20) and two independent cohorts of human breast cancer patients (n=85) and healthy individuals (n=30). The results were analyzed statistically, and associations between clinicopathological and survival data were evaluated by multivariate Cox regression analysis.
Results: SLC50A1 was confirmed as a candidate breast cancer gene by bioinformatics analysis. SLC50A1  mRNA expression levels were significantly upregulated in breast cancer (P <0.001). Serum SLC50A1 levels were able to discriminate between women with breast cancer and healthy women with a sensitivity of 75.3% and a specificity of 100.0% (P <0.001; area under the curve=0.915). Interestingly, SLC50A1 protein expression was associated with estrogen receptor (P =0.016) and HER2 status (P =0.037). Furthermore, SLC50A1 levels were positively related to unfavorable 3-year outcomes in patients with high-grade breast cancer (HR =1.823, P =0.01), indicating its potential use as an independent prognostic factor.
Conclusion: SLC50A1 can be used as a serum-based diagnostic and prognostic biomarker in breast cancer. However, further studies are needed to clarify its potential role as a therapeutic target.
Keywords: breast cancer, SLC50A1, biomarker, serum, prognosis