Interestingly, Li et al recently found that prostaglandin E2 (PGE2) was secreted by BMSCs in response to cancer cell-derived IL-1 and that the BMSC-derived PGE2 significantly enhanced the CSCs population via Akt/GSK-3/β-catenin signalling axis (Li et al, 2012). The gene discussed is IL1A; the disease is cancer.