Given the recent findings that S1P1 is important for TNBC survival [22,23], we next performed a Western blot analysis to assess the protein levels of S1P1 in a panel of human TNBC and less aggressive luminal breast cancer cell lines, as well as a nontransformed breast epithelial cell line (MCF10A) (Figure 1d). This evidence concerns the gene S1PR1 and breast carcinoma.