Figure 3.

 (A) Immunohistochemical demonstration of cytokeratin (AE1/AE3 antibodies) in cells with squamous differentiation. The asterisk indicates the keratin positive cells with squamous differentiation. All cells with squamous differentiation stained positively. The adenocarcinoma cells neighbouring the squamous differentiation tissue (arrowheads) were also immunopositive (endometrioid carcinoma). Original magnification, ×150. (B) Immunohistochemical demonstration of involucrin in tissue with squamous differentiation. The asterisk indicates involucrin positive cells (squamous differentiation tissue). Original magnification, ×150. Arrowheads indicate morules that are negative for involucrin (same case as that shown in fig 1D). (C) Immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA) in morules. The arrow indicates morules. PCNA was detected in the nuclei of the cancer cell, but not in the morules (endometrioid carcinoma). Original magnification, ×100.