A method for promoting expression of p53 mRNA and an expression promoting agent for use in the method are provided. The expression of the p53 gene can be promoted by inhibiting the binding between RNA transcribed from exon 1 of the vegf-A gene and mRNA transcribed from the p53 gene. The inhibition of the binding can be achieved by, for example, degrading the RNA transcribed from the exon 1 of the vegf-A gene, inhibiting transcription of RNA from the exon 1 of the vegf-A gene, or binding a nucleic acid that is different from the mRNA transcribed from the p53 gene to the RNA transcribed from the exon 1 of the vegf-A gene.