As for the potential role of CSC maintenance in tumor recurrence and metastasis, autophagic cancer-associated fibroblasts (CAFs) have been shown to be important for luminal breast cancer progression promotion via the HMGB1-TLR4 signaling pathway, and CAF autophagy and TLR4 in breast cancer cells are potential therapeutic targets [75]. Here, HMGB1 is linked to cancer.