SFRP4 and tongue cancer: Warrier et al. [103] have demonstrated the ability of sFRP4, an endogenously produced Wnt antagonist, to suppress CSC proliferation and increase these cells’ sensitivity to chemotherapy in the laryngeal cancer cell line Hep2 (Cellosaurus HEp-2, CVCL_1906) and tongue cancer cell line KB (Cellosaurus KB, CVCL_0372).