Lactate dehydrogenase in retinoblastoma: an immunohistochemical study of twelve eyes

Specific immunohistochemical localization of lactate dehydrogenase (LDH isoenzyme 1) in well-differentiated retinoblastomas revealed the presence of this enzyme predominantly in the cytoplasm of cells that form Flexner-Wintersteiner and Homer Wright rosettes. Malignant cells of poorly differentiated retinoblastomas also contained the reaction product for LDH, but the intensity of the reaction was much less. LDH was also present in the corneal epithelium, corneal endothelium, ciliary muscle, nonpigmented ciliary epithelium, iris muscle, lens epithelium, lens cortex, pigment epithelium and the neurosensory retina. This specific immunohistochemical localization revealed distribution of this enzyme primarily in those ocular structures that have a relatively high rate of metabolism, as well as in various cellular components of retinoblastomas.