STAT3 and breast cancer: Such a phenotype is even more abundant in triple-negative breast cancer (TNBC) cell lines because the TNBC cell lines are more dependent on STAT3 phosphorylation, whereas autophagy can upregulate p-STAT3; when autophagy is inhibited, p-STAT3 is downregulated and tumor cell growth is inhibited in autophagy-dependent breast cancer cell lines.