ABCG2 and dysplasia: Overall, ABCG2 antigen stain intensity increased with disease severity, although this trend was only modestly evident from the immunoreactivity index scores: mild dysplasia (median score = 1; IQR = 0–1) < moderate-severe dysplasia (median score = 1; IQR = 1–2) <OSCC tissue (median score = 1.1; IQR = 1–2; Fig. 4).