[HLA class I antigen expression correlates with histological cell type in uveal melanoma].
OBJECTIVE
The prognosis of uveal melanoma is correlated with its histologic cell type. The epithelioid cell type is associated with a higher metastatic rate than the spindle cell type. The Human Leucocyte Antigen Class I (HLA-I) expression of the melanoma also correlates with the prognosis. In this study, we analyzed HLA-I antigen expression of uveal melanomas to determine whether a relationship exist between antigenic expression and melanoma cell type.


METHODS
Formalin-fixed, paraffin-embedded spindle cell type (n = 11) and epithelioid cell type (n = 11) uveal melanomas were immunostained with the HC10 antibody (1:80) for HLA-I antigen expression with appropriate positive and negative controls. Sections were assessed semiquantitatively according to the percentage of stained cells.


RESULTS
Among the spindle cell type melanomas, 2 out of 11 (18%) stained with HC10 antibodies. The staining intensity was less than 25% of the cells in these two melanomas. Among the epithelioid cell type melanomas, 9 out of 11 (82%) stained with HC10. The staining intensity was more than 25% of the cells in 5 of these 9 melanomas.


CONCLUSIONS
It is unknown why spindle and epithelioid cell type uveal melanomas have different prognoses. Human uveal melanoma cell lines with low HLA-I expression are susceptible to NK cell-mediated lysis in vitro and in murine studies. The prognostically more favorable spindle cell type melanoma expresses less HLA-I than the epithelioid cell type melanoma. These results stress the role of NK cells in the rejection of uveal melanoma.
Dithmar
S
S
Universitäts-Augenklinik Heidelberg, lm Neuenheimer Feld 400, 69120 Heidelberg.
Crowder
J
J
Jager
M J
MJ
Vigniswaran
N
N
Grossniklaus
H E
HE
D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D008545:Melanoma / Q000145:classification / Q000473:pathology*; D011379:Prognosis; D014602:Uvea / Q000473:pathology; D014604:Uveal Neoplasms / Q000145:classification / Q000473:pathology*
D015395:Histocompatibility Antigens Class I