ALDH1A1 and head and neck squamous cell carcinoma: In addition, EGF not only increased vimentin expression but also significantly enhanced the expression of aldehyde dehydrogenase 1 (ALDH1) and Bmi-1 (Figure 2B and 2C), another two stem cell-related genes popularly expressed in CSC-like cells in HNSCC [19, 22].