BCL11B and head and neck squamous cell carcinoma: We therefore performed immunoflourescent co-staining for CTIP2 and BMI1 protein, in well, moderately and poorly differentiated HNSCC samples to see if some of the CTIP2 expressing cells also express the cancer stem cell (CSC) marker BMI1, previously implicated in self renewal and tumorigenesis [30], [31], [32], [33], [34], [35], [36], [37].