Expression of cancer stem cell markers ALDH1 and Bmi1 in oral erythroplakia and the risk of oral cancer

J Oral Pathol Med (2013) 42 : 148–153 Background: Oral erythroplakia (OE) is a notoriously aggressive oral pre‐malignant lesion with a high tendency to oral cancer development, but its biological behavior is largely unknown. The objective of this study was to determine the expression of cancer stem cell markers ALDH1 and Bmi1 in OE and their correlation with malignant transformation of OE. Methods: In a retrospective case–control study, expression patterns of ALDH1 and Bmi1 were determined using immunohistochemistry in samples from 34 patients with OE, including patients with untransformed lesions (n = 17) and patients with malignant transformed lesions (n = 17). Results: ALDH1 and Bmi1 expression was observed in 19 (55.9%) and 20 (58.8%) of 34 patients with OE, respectively. Multivariate analysis revealed that ALDH1 expression was significantly associated with increased risk of transformation (P < 0.05), but Bmi1 expression was not a significant marker (P > 0.05). Notably, the coexpression of both ALDH1 and Bmi1 was a strong indicator associated with 8.56‐fold (95% confidence interval [CI], 1.74–42.17; P < 0.01) for malignant transformation. Point prevalence analysis revealed that 78.6% (95% CI, 54.0–100) of the patient with coexpression of both ALDH1 and Bmi1 developed oral cancer. Conclusion: Our data indicated that the expression patterns of ALDH1 and Bmi1 in OE were associated with malignant transformation, suggesting that they may be valuable predictors for evaluating the risk of oral cancer.