It was reported that COX-2/PGE2 signaling can enhance cancer stemness (Rudnick et al. 2011; Li et al. 2012a; Thanan et al. 2012; Zhang et al. 2013), and impact the immune response to cancer cells by decreasing dendritic cell (DC) activity, reducing DC maturation, hindering antigen presentation, and activating T cells (Zhang et al. 2013). Here, PTGS2 is linked to cancer.