Expression of the
gangliosides GM3, GD3 and GD2 was studied in tissue sections from 19 naevi, 29 primary and 83 metastatic
melanoma using the ABC immunoperoxidase technique. GM3 was not detected in normal skin whereas GD2 was detected on the basal and stratum spinosum of the epidermis and on peripheral nerves in the dermis. GD3 was expressed on melanocytes but not on most other components of normal skin. However, GD3 was strongly expressed on epidermis adjacent to naevi and primary
melanoma whereas GD2, in contrast to that in normal skin, was not expressed on the epidermis adjacent to 26/29 primary
melanoma. All naevi were positive for GM3 and GD3 except that GM3 was not detected on junctional components of naevi. GD2 was not expressed on naevi except in areas showing neuroid differentiation. Studies on
melanoma revealed that approximately 60% of primary and 75% of metastatic
melanoma expressed GM3 to a varying extent. With 2 exceptions, all primary and metastatic
melanomas expressed GD3 although there was variable expression within most of the individual tumours. GD2 was detected in only approximately 25% of primary and 50% of metastatic
melanomas. Both GD2 and GD3 were detected on lymphocytes surrounding
melanoma. The higher expression of GD2 on
metastases compared to primary
melanomas was consistent with the view that GD2 expression was associated with increased metastatic potential. However, the low proportion of
metastases expressing GD2 and the absence of any correlation with thickness of the primary tumour suggested that GD2 expression was not a reliable marker of metastatic potential. No differences could be detected in
ganglioside expression on
metastases in skin or lymph nodes. These results appear to have implications for the use of MAbs against
gangliosides in
therapy of
melanoma and in the study of melanocytic differentiation.