Fig. 3

Patient 8 biopsy specimen with non-keratinizing oropharyngeal carcinoma compared with concurrent non-neoplastic mucosa. Enhancer of zeste homolog 2 (EZH2) and Ki-67 (G1, S, G2 and M phases of the cell cycle) show strong (3+ on a scale of 0-3+) nuclear expression in a majority of the non-keratinizing squamous cell carcinoma (NKSCC) versus similar expression primarily limited to the basal and suprabasal cells of the non-neoplastic squamous mucosa (Frames a and c versus b and d, respectively). Mitotic progression in the corresponding H&E coincides with the EZH2 and Ki-67 expression with multiple mitotic figures evident in the NKSCC (Frame e) with no mitotic figures in the adjacent non-neoplastic squamous mucosa (Frame f). (DAB brown chromogenic signal for frames a-d; original magnifications ×200 for frames a-d and ×400 for Frames e and f)