We describe the expression of 18 different
cell adhesion molecules, intermediate filaments and
Ki-67 antigen in embryonal childhood
tumors. 5 microns frozen sections from 15
nephroblastomas, 13
neuroblastomas, six
rhabdomyosarcomas, one
Ewing sarcoma and one
pulmonary blastoma were analyzed by the
alkaline phosphatase anti-
alkaline phosphatase (APAAP) method using murine
monoclonal antibodies. All
tumors exhibited high proliferation rates as did, surprisingly, the
nephroblastoma specimens despite pre-treatment with
chemotherapy. Polysialylated
NCAM was demonstrated on all
tumor types, but
Ewing sarcoma and expression correlated inversely with cell differentiation. In contrast,
E-cadherin was present solely on tubulus like cells in
nephroblastomas. This cell type showed a coexpression of
cytokeratin and
vimentin, giving evidence of its intermediate position between the mesenchyme and epithelium. In
neuroblastomas, CD44s (hyaluronate receptor) expression was increased with cell differentiation.
ICAM-1,
VCAM-1 and
E-selectin were mostly expressed in regressive areas of pretreated
nephroblastoma specimens where a considerable infiltration of leukocytes was noted as well. Since endothelial and
leukocyte adhesion molecules were distinctly less expressed in all other
tumors investigated, these findings may indicate immunological processes as a consequence of or as supplement to the chemotherapeutical effect on
nephroblastoma cells.
Integrin receptors were not found on the surface of
tumor cells, and therefore, at least those investigated seem to be of secondary importance to the biology of the
tumors studied herein. In conclusion, our investigations demonstrate that, besides achieving a secure and prompt differentiation between various embryonal
tumors, applying the panel of
monoclonal antibodies proposed herein gives interesting insights into the histogenesis, biology and metastatic potential of pediatric
malignancies.