MUC16 as a sensitive and specific marker for epithelial downgrowth

Abstract

Objective: To compare immunohistochemical results of cytokeratin AE1/AE3, the traditional favored marker, with MUC16 and cytokeratin 19 for diagnostic sensitivity and specificity in epithelial downgrowth and control corneas.

Methods: Immunohistochemical analysis was performed in 5 cases of epithelial downgrowth and 5 control specimens for MUC16, cytokeratin AE1/AE3, and cytokeratin 19 using the immunoperoxidase method. The mean percentages of reactive cells on the epithelium and endothelium were compared for each antibody using the Wilcoxon rank sum test. The sensitivity and specificity for each marker were compared.

Results: All 3 antibodies showed high sensitivity (100%) in identifying epithelial downgrowth. However, the specificity was greatest for MUC 16 (100%) compared with cytokeratin 19 (80%) and cytokeratin AE1/AE3 (0%). None of the endothelial cells in any case showed reactivity to anti-MUC16 compared with anti-cytokeratin AE1/AE3 (mean [SD], 0.0% [0.0%] vs 17.4% [10.4%]; P = .008). Cytokeratin 19 was positive in every case of epithelial downgrowth but showed focal staining of the endothelium (3.4% of cells) in 1 control.

Conclusions: Antibodies for MUC16, cytokeratin AE1/AE3, and cytokeratin 19 are equally sensitive for downgrowth. However, anti-MUC16 showed superior specificity compared with anti-cytokeratin 19 or anti-cytokeratin AE1/AE3 in this study.

Figure 1

Failed Descemet stripping automated endothelial keratoplasty specimen demonstrating a thin layer of cells on the posterior corneal surface in a case of epithelial downgrowth (hematoxylin-eosin, original magnification ×250).

Figure 2

Percentage of immunoreactive cells for MUC16, cytokeratin AE1/AE3, and cytokeratin 19 in control corneas.

Figure 3

Percentage of positively stained cells for MUC16, cytokeratin AE1/AE3, and CK19 in epithelial downgrowth specimens.

Figure 4

Representative immunohistochemical images of MUC16, cytokeratin AE1/AE3, and cytokeratin 19 expression (original magnification ×250). A, Lack of immunoreactivity of the endothelium in controls for MUC16. B, Cytokeratin AE1/AE3 staining of the endothelium in controls. C, Lack of reactivity of the endothelium in controls for cytokeratin 19. D, MUC16 staining of the posterior surface of epithelial downgrowth specimens. E, Cytokeratin AE1/AE3 staining of the posterior surface of epithelial downgrowth specimens. F, Anti–cytokeratin 19 reactivity of the posterior surface of epithelial downgrowth specimens.