CD44 and breast carcinoma: Together, our results confirmed that the CD133+ population in prostate cancer cells and CD44+/high/CD24−/low population in breast cancer MCF7 cells possessed typical stemness-associated characteristics, consistent with previous reports.9, 32, 33, 34, 35, 36 Thus, these cells, hereafter referred to as CSCs, were further used to understand the signaling mechanisms activated by neuropeptides.