A method of evaluating the degree of cancerization of a specimen originating in a mammal characterized by comprising: (1) the first step of measuring the methylation frequency in G protein-coupled receptor 7 gene contained in the mammal-origin specimen and (2) the second step of judging the degree of cancerization of the above-described specimen based on the difference obtained by comparing the methylation frequency having been measured above with the data of a control and so on.