Fig. 2

Photomicrographs of two different types of OSCCs. A1-A3: SSC-1, well differentiated with many cancer pearls. B1-B3: SSC-2, poorly differentiated with numerous infiltrating tumor islets. A1, A2, B1, B2: hematoxylin and eosin staining. A3 and B3: Immunostaining without background stain. A3: p53 staining is strongly positive in the tumor cells (arrows). B3: KRAS staining is strongly positive in the tumor cells (arrows)