To obtain a new DNA which contains a specific base sequence, comprises a p73 promoter active DNA, exhibits antitumor effect on the malignant tumor cell of which p53 gene deactivated in the greater part of human tumor is deactivated and is useful in the search or the like of antitumor substances.

This DNA is a new DNA which at least contains the base sequence represented by the formula and exhibits p73 promoter activity, exerts antitumor effect peculiarly on the malignant tumor cell of which p53 gene deactivated in at least about 50% of human tumor is deactivated without affecting the normal cell and not only permits the chemotherapy for malignant cell or the chemical preventive but also is useful in the screening or the like of antitumor active substances. This DNA is obtained as p73 promoter capable of activating tumor cell multiplication inhibitor or apoptosis induction active p73 gene by synthesizing an oligonucleotide comprising 72 bases in an exon part of p73 gene and screening out a human leukocyte genomic library by using this oligonucleotide as a probe.