PTGS2 and liver cancer: Zhou et al.344 found that LPS activates the TLR4–AKT–SOX2 signaling pathway of liver cancer cell lines to improve the ability of cancer stem cells; Lin et al.345 found that there is a positive feedback loop of COX-2/PGE2/signal transducer and activator of transcription factor 3 (STAT3) activated by LPS in liver cancer cells, which regulates the expression of genes related to tumor proliferation, differentiation, and apoptosis.