BMI1 and oral cavity squamous cell carcinoma: Semi-quantitative real-time PCR analysis of ABCG2 and Bmi-1 gene expression in eight oral cell lines originating from normal tissue (OKF6-TERT2), mild dysplasia (DOK), severe dysplasia (POE-9n), and oral squamous cell carcinoma (PE/CA PJ15, SCC04, SCC25, SCC09 and SCC15) are provided in Figure 2 and Table 2.