Expression of the c-kit receptor characterizes a subset of neuroblastomas with favorable prognosis

Expression of the c-kit proto-oncogene product in neuroblastomas has been reported, but its clinical relevance is unclear. We determined the expression of c-kit by immunohistochemistry in a series of 155 neuroblastomas with long-term follow-up. The specificity of the reaction was verified by Western blot analysis and quantitative RT-PCR, and exon 11 of the kit gene was screened for mutations by PCR and capillary electrophoresis. No mutations were detected, and transcription of the kit gene correlated with protein expression. c-kit expression was associated with lower tumor stages and a low rate of MYCN amplification. More importantly, it coincided with tumor differentiation (P