Enolase isoenzymes in benign and malignant melanocytic lesions.

The distributions of the alpha, beta and gamma subunits of enolase were studied in 34 melanocytic lesions using the peroxidase-antiperoxidase (PAP) technique. Melanocytes in benign neoplasms stained moderately strongly for both alpha enolase and gamma enolase but staining for beta enolase was consistently negative. Staining for alpha enolase was always stronger than that for gamma enolase. There are some indications that with increasing degrees of dedifferentiation there was a reduction of gamma enolase activity, least differentiated cells being completely negative. Ocular melanomata showed similar changes to those seen in the skin. The enolase isoenzyme composition of tumour extracts was assessed biochemically on a limited number of cases and these results are discussed in relationship to the immunohistochemical studies.