PURPOSE: To obtain the subject new DNA existing in the seventh chromosome long arm, coding a human DNA mismatch repair-relating protein having a specific base sequence, used for the analysis or diagnosis of genes with the gene, etc., and enabling the risk diagnosis or early discovery of cancers, etc.

CONSTITUTION: A DNA coding the human DNA mismatch repair-relating protein consisting of six kinds of new DNAs comprising sequences each of which contains the sequence of the formula, or a DNA containing the new DNAs, and a gene coding the human DNA mismatch repair-relating protein. The DNA is used as a primer or probe in a gene-analyzing or diagnosing method utilizing the gene, etc., used for the isolation, immobilization, etc., of the gene coding a protein related to the DNA mismatch-repairing mechanisms of man or a higher organism, and further, used for the risk diagnosis, prophylactic treatment, early discovery, or progress observation of cancers, etc. The DNA is obtained by cloning the cDNA library of a human fetal brain on the basis of a partial sequence well stored in the DNA mismatch-repairing protein gene of a bacterium or yeast.