Aa. Jungbluth et al., Expression of melanocyte-associated markers gp100 and Melan-A/MART-1 in angiomyolipomas - An immunohistochemical and rt-PCR analysis, VIRCHOWS AR, 434(5), 1999, pp. 429-435
Citations number
60
Categorie Soggetti
Medical Research Diagnosis & Treatment
Journal title
VIRCHOWS ARCHIV-AN INTERNATIONAL JOURNAL OF PATHOLOGY
Angiomyolipomas are tumours of uncertain histogenesis, most often occurring
in association with the kidney. A characteristic finding is their reactivi
ty with HMB-45, a monoclonal antibody to the melanocyte-associated antigen
gp-100. We tested 18 angiomyolipomas for their reactivity with A103, a mono
clonal antibody to Melan-A (MART-I), another melanocyte-associated marker,
and compared it with HMB-45. All cases were positive with both antibodies,
yet most cases showed a more homogeneous staining pattern with A103. Normal
kidney was immunohistochemically negative for both antibodies. We also per
formed RT-PCR assays for gp-100 and Melan-A in 4 of the 18 angiomyolipoma s
amples and in three normal kidney samples. All 4 angiomyolipoma specimens r
evealed mRNA for both melanocyte differentiation markers. gp-100 mRNA was f
ound in the samples of normal kidney, but Melan-A mRNA was not. Our study s
hows that angiomyolipomas express the melanocyte-associated antigens Melan-
A and gp-100 at the protein and at the mRNA level, suggesting a true expres
sion of these antigens rather than cross-reacting epitopes. Based on the mR
NA expression pattern, immunohistochemical analysis is the preferred method
for the detection of gp-100, while Melan-A can be used at the protein and
mRNB levels. Our study demonstrates that A103 is a useful marker for the di
agnosis of angiomyolipomas.