The differential diagnosis of
neuroblastoma from other small round-cell
tumors of childhood, although clinically of great importance, is sometimes difficult due to the almost indistinguishable appearance of such
tumors by conventional microscopy. Because
neuroblastomas are characterized by the synthesis of
catecholamines, we investigated the possibility that expression of genes involved in this pathway could serve as a molecular marker for this disease. A
reverse transcriptase polymerase chain reaction assay was used to analyze expression of
tyrosine hydroxylase and
dopa decarboxylase in 84 pediatric
malignancies including 55
neuroblastomas, 6 Ewing's
sarcomas/
primitive neuroectodermal tumors, 7
lymphomas, 6
leukemias, 2
rhabdomyosarcomas, 6
osteosarcomas, and 2 phaeochromocytomas. Of the 55
neuroblastoma samples analyzed, 54 expressed clearly detectable levels of both genes. The one sample that did not express either of the genes was rediagnosed both clinically and by molecular genetic analysis as a
Ewing's sarcoma. Of the 29 non-
neuroblastoma tumor samples examined, the only
tumor samples that expressed clearly detectable levels of both
tyrosine hydroxylase and
dopa decarboxylase were phaeochromocytomas. Like
neuroblastomas, these
tumors are characterized by high levels of
catecholamines. These findings suggest that expression of genes involved in
catecholamine biosynthesis may be useful for differentiating
neuroblastoma from other small round-cell
tumors of childhood.