High nm23-H1/NDPK-A expression in Ewing tumors: paradoxical immunohistochemical reactivity and lack of prognostic significance.
Expression of nm23-H1/NDPK-A has been reported to correlate inversely with metastasizing potential of rodent experimental cells and some human tumors. In the search for reliable molecular prognostic indicators for Ewing tumors (ET), a group of aggressive presumably neuroectodermal malignancies in children and adolescents, we studied nm23-H1/NDPK-A expression. Northern-blot and RT-PCR analyses were employed to semi-quantificatively measure nm23-H1 mRNA levels in ET cell lines and tissue extracts. A panel of monoclonal antibodies (MAbs) were used to evaluate protein abundance by Western blotting and immunohistochemistry. The nm23-H1/NDPK-A gene was also investigated on the DNA level to define possible genomic alterations. Our results revealed neither nm23-H1 allelic loss nor gene amplification and failed to show any significant variation in nm23-H1 mRNA or NDPK-A protein levels of primary or metastatic ET. NDPK-A protein levels were high and comparable to those of MCF-7 breast-cancer cells and to aggressive stage-IV neuroblastoma cell lines. nm23-H2/NDPK-B expression in ET was slightly more variable but generally lower than in MCF-7 cells. In the immunohistochemical analysis, however, discrepancies in the reactivity patterns with different antibodies were observed. Differential sensitivity to various fixation methods and heat treatment pointed to a structurally polymorphic NDPK-A protein. nm23-H1 expression studies using immunohistochemistry for prognostic counselling should thus be interpreted with caution.
Aryee
D N
DN
Children's Cancer Research Institute, St Anna Kinderspital, Vienna, Austria.
Ströbel
T
T
Kos
K
K
Salzer-Kuntschik
M
M
Zoubek
A
A
Veron
M
M
Ambros
I M
IM
Traincart
F
F
Gadner
H
H
Kovar
H
H
D000293:Adolescent; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D002648:Child; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D054778:NM23 Nucleoside Diphosphate Kinases; D009701:Nucleoside-Diphosphate Kinase / Q000032:analysis*; D016133:Polymerase Chain Reaction / Q000379:methods; D011379:Prognosis; D012194:RNA-Directed DNA Polymerase; D012512:Sarcoma, Ewing / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics / Q000556:secondary; D014157:Transcription Factors / Q000032:analysis*
D000911:Antibodies, Monoclonal; D054778:NM23 Nucleoside Diphosphate Kinases; D014157:Transcription Factors; C517938:NME1 protein, human; D009701:Nucleoside-Diphosphate Kinase; D012194:RNA-Directed DNA Polymerase; D020559:Monomeric GTP-Binding Proteins