Fig. 1

Immunostaining for LMP-1 in representatives of normal oral mucosa (a), oral leukoplakia (OL) without dysplasia (b), OL with dysplasia (c and d) and oral squamous cell carcinoma (OSCC) (e and f). In normal oral mucosa (a) and OL without dysplasia (b), LMP-1 is predominantly found in nuclei of prickle cells (arrowheads) and focally detected in basal (arrow) and parabasal cells. Similarly in OL with dysplasia (c), staining is predominantly found in the nuclei of prickle cells (arrowheads). The cytoplasmic staining alone (white arrows) and nuclear plus cytoplasmic staining (white arrowheads) were also observed in many prickle cells of OL with dysplasia (d). In OSCC, nuclear staining (arrowheads) can be observed in tumor cells (e). Additionally, many nuclear plus cytoplasmic stained cells (white arrowheads) and a few cytoplasmic stained cells (white arrows) are also detected (f). Scale bar = 50 μm