High SLC20A1 expression is associated with poor prognoses in claudin-low and basal-like breast cancers

Background/Aim: SLC20A1 has been identified as a prognostic marker in ER+ breast cancer. However, the role of SLC20A1 expression in breast cancer subtypes other than the ER+ types remains unclear. Materials and Methods: Genomics datasets were downloaded and analyzed, and the effect of SLC20A1 knockdown using targeted siRNA on cell viability and tumor-sphere formation was assessed. Results: SLC20A1high patients with ER+, claudin-low or basal-like breast cancers showed poor prognoses. SLC20A1high patients treated with radiotherapy had poor clinical outcomes. SLC20A1 knockdown suppressed the viability of MDA-MB 231 (claudin-low), MDA-MB 468 (basal-like) and MCF-7 (ER+) cells, and tumor-sphere formation by ALDH1high cells. These results suggest that SLC20A1 is involved in cancer progression and contributes to clinical outcomes in patients with ER+, claudin-low and basal-like breast cancers. Conclusion: SLC20A1 is a potential prognostic marker and therapeutic target in ER+, claudin-low and basal-like breast cancers.