STAT3 and breast cancer: Similarly, the knockdown of circNOLC1 inhibited the SP ratio in MDA-MB-231 and MDA-MB-468 cells, while the STAT3 overexpression reversed the inhibition (Fig. 8D and E), implying that the overexpression of STAT3 rescues circNOLC1 depletion-attenuated proliferation and cancer stem cell activity of breast cancer.