To confirm transgene expression, we first performed immunofluorescence staining of B16 (mouse melanoma, wild-type p53, p19Arf null) and C6 (rat glioma, wild-type p53, p19Arf null) cells transduced with pCLPGp19 or, as a control, with the empty pCLPG retrovirus. This evidence concerns the gene TP53 and central nervous system cancer.