ALDH1A1 and dysplastic oral keratinocyte: The mean expression scores of ALDH1 were 78.4 ± 1.9, 69.1 ± 6.4, and 41.6 ± 3.1 in OSCC, oral epithelial dysplasia, and normal mucosa, respectively; furthermore, a significant difference between ALDH1 staining in OSCC and normal oral mucosa was observed (P < 0.01).