POU5F1 and cancer: IL-33 can bind to its receptor in TAMs, IL-1RL1, to induce TGF-β secretion by TAMs; while it can also bind to IL-1RL1 in other cancer cells to increase the population of CSCs through inducing the expression of stem cell genes (NANOG, NOTCH3, OCT3 and OCT4) as well as increase chemoresistance of cancer cells [27].