ATP1B1 and cancer: We observed that cells double-positive for NRP1 and FXYD3 (ancestor-like CSC enriched) among the NRP1-positive cells or cells double-positive for IGF1R and FXYD3 (ancestor-like CSC enriched) among the IGF1R-positive cells were increased in cancer tissues after paclitaxel treatment, whereas they were diminished in ATP1B1-knockdown cancer tissues (Figure 7C and Supplemental Figure 10B).