BMI1 and head and neck squamous cell carcinoma: In this study, we examined whether cigarette smoke condensate (CSC) was associated with HNSCC via induction of OCT-4, and whether such induction promoted the development of HNSCC by increasing the expression of ID1, NF-κB, and the cancer stem cell markers, B lymphoma Mo-MLV insertion region 1 homolog (BMI-1) 13 and CD44 14.