IL4 and neoplasm: However, the authors discovered that the molecules involved in the polarization of T helper cells towards Tregs (IL-4, IL-6, IL-15 and PG-E2) were expressed not only by HRS cells but also by the TME [23], suggesting that tumor-educated noncancerous cells, such as TAMs or CAFs, can help tumor cells to build the immunosuppressive TME [19].