Adjuvants, Immunologic/pharmacology; Antigens, Surface/biosynthesis; Antineoplastic Agents/pharmacology; Eye Neoplasms/immunology; Immunoglobulins/biosynthesis; Retinoblastoma/immunology; Tretinoin/pharmacology; Antigens, Surface/analysis; Antigens, Surface/genetics; Cell Differentiation/drug effects; Dose-Response Relationship, Drug; Eye Neoplasms/metabolism; Eye Neoplasms/pathology; Flow Cytometry; Gene Expression Regulation, Neoplastic/drug effects; Histocompatibility Antigens Class I/analysis; Histocompatibility Antigens Class I/biosynthesis; Histocompatibility Antigens Class I/genetics; Histocompatibility Antigens Class II/analysis; Histocompatibility Antigens Class II/biosynthesis; Histocompatibility Antigens Class II/genetics; Humans; Immunoglobulins/analysis; Immunoglobulins/genetics; Immunohistochemistry; Intercellular Adhesion Molecule-1/analysis; Intercellular Adhesion Molecule-1/biosynthesis; Intercellular Adhesion Molecule-1/genetics; Neural Cell Adhesion Molecules/analysis; Neural Cell Adhesion Molecules/biosynthesis; Neural Cell Adhesion Molecules/genetics; Retinoblastoma/metabolism; Retinoblastoma/pathology; Thy-1 Antigens/analysis; Thy-1 Antigens/biosynthesis; Thy-1 Antigens/genetics; Time Factors; Tumor Cells, Cultured