Additionally, a recent study using a murine model of squamous cell carcinoma reported that tumor-initiating cells (TICs) promoted the release of IL-33 and facilitated the differentiation of macrophages expressing FcεRIα+ that in turn exerted paracrine TGF-β signals to TICs with inducible invasive and drug-resistant properties, while further upregulating IL-33 [124]. The gene discussed is IL33; the disease is squamous cell carcinoma.