BCL2 and in situ carcinoma: Mechanistically, we recently demonstrated that SF enhanced the cytotoxicity of chemotherapy (CIS or 5-FU) against HNSCC by stimulation of the caspase-dependent apoptosis pathway.13 In the current study, we reported comparable results on HNSCC–CSCs, such as SF increased the apoptotic effect of CIS and 5-FU on CSCs by inhibiting BCL2.