Decreased N-myc expression in human medulloblastoma cell lines during differentiation.

Medulloblastoma is the most common primitive neuroectodermal tumor of the central nervous system, and shares some biochemical and immunological features with neuroblastoma. It could be suggested that N-myc expression in medulloblastoma is correlated with primitiveness or cell differentiation, as in neuroblastoma. N-myc expression in two human medulloblastoma cell lines (ONS-76 and -81) was investigated during drug-induced differentiation by immunocytochemistry and Western blotting. The growth rates of the two medulloblastoma cell lines showed a marked decrease and morphological differentiation occurred after treatment with 1 mM dibutyryl cyclic-adenosine 3',5'-monophosphate (dbt-cAMP). The decrease in N-myc expression with differentiation of cells was confirmed by immunocytochemistry and Western blotting. We believe that decreased N-myc expression is correlated with cell differentiation, and a decrease in the primitiveness of medulloblastoma cells.