Immunocytochemical staining of cell type-specific markers demonstrated that the ALI cultures contain populations of different cell types present in the human OM in vivo, including an average of 12% of goblet cells (Mucin 5AC + cells), and 4–5% sustentacular cells (Cytokeratin-18 + cells) (Fig. 2a, b; Additional file 1: Fig. S1c, d). The gene discussed is MUC5AC; the disease is ocular melanoma.