According to an aspect of the present invention, similarity centrality measures that are centrality measures of proteins that a protein similarity network includes are calculated, interaction centrality measures that are centrality measures of the proteins that the protein-protein interaction network includes are calculated, a rejection score that represents probability of a compound to be validated to be classified as a rejected drug is calculated using classifiers that use, as training data, the approval attributes of the respective drugs, the sum and average of the similarity centrality measures per target for each drug, and the sum and average of the interaction centrality measures per target for each drug, and the rejection score is output.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. An approval prediction apparatus comprising an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that is constructed according to the similarity between proteins; a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; and an interaction network information storage unit that stores interaction network information on a protein-protein interaction network that is constructed based on interactions between the proteins; and the control unit includes: a similarity centrality measure calculating unit that, based on the similarity network information stored in the similarity network information storage unit, calculates similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an interaction centrality measure calculating unit that, based on the interaction network information stored in the interaction network information storage unit, calculates interaction centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein-protein interaction network includes; a rejection score calculating unit that calculates a rejection score that represents probability of a compound to be validated to be classified as a rejected drug, using classifiers that use, as training data, the approval attributes of the respective drugs stored in the drug target storage unit, the sum and average of the similarity centrality measures per target for each drug that are calculated by the similarity centrality measure calculating unit, and the sum and average of the interaction centrality measures per target for each drug that are calculated by the interaction centrality measure calculating unit; and a rejection score outputting unit that outputs, via the output unit, the rejection score that is calculated by the rejection score calculating unit. 2. An approval prediction apparatus comprising an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that includes proteins having similarity; and a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; and the control unit includes: a similarity centrality measure calculating unit that, based on the similarity network information stored in the similarity network information storage unit, calculates similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an approval determining unit that, based on the approval attributes of the drugs targeting the proteins according to the protein information stored in the drug target storage unit, which are the proteins that the protein similarity network includes, obtains a determination result representing whether the proteins to be validated, which are proteins that the similarity network includes, are within a range of targets of approved drugs or a range of targets of rejected drugs, using the similarity centrality measures of the proteins to be validated that are calculated by the similarity centrality measure calculating unit; and a determination result outputting unit that outputs, via the output unit, the determination result that is obtained by the approval determining unit. 3. The approval prediction apparatus according to claim 1, wherein the storage unit further includes a protein sequence information storage unit that stores sequence information on amino acid sequences of the proteins, and the control unit further includes a similarity network information storing unit that, when the similarity is detected between the proteins using a signature-based algorithm and based on the sequence information stored in the protein sequence information storage unit, creates the protein similarity network including the proteins between which the similarity is detected and stores the similarity network information on the protein similarity network in the similarity network information storage unit. 4. The approval prediction apparatus according to claim 2, wherein, based on the approval attributes of the drugs targeting the proteins according to the protein information stored in the drug target storage unit, which are the proteins that the protein similarity network includes, the approval determining unit generates a determination result representing that the proteins to be validated are within the range of targets of rejected drugs when the degree centrality contained in the similarity centrality measures of the proteins to be validated that are calculated by the similarity centrality measure calculating unit is high, the closeness centrality is low, and the Burt's constraint is extremely low. 5. An approval prediction method executed by an approval prediction apparatus including an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that is constructed according to the similarity between proteins; a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; and an interaction network information storage unit that stores interaction network information on a protein-protein interaction network that is constructed based on interactions between the proteins; the method executed by the control unit comprising: a similarity centrality measure calculating step of, based on the similarity network information stored in the similarity network information storage unit, calculating similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an interaction centrality measure calculating step of, based on the interaction network information stored in the interaction network information storage unit, calculating interaction centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein-protein interaction network includes; a rejection score calculating step of calculating a rejection score that represents probability of a compound to be validated to be classified as a rejected drug, using classifiers that use, as training data, the approval attributes of the respective drugs stored in the drug target storage unit, the sum and average of the similarity centrality measures per target for each drug that are calculated at the similarity centrality measure calculating step, and the sum and average of the interaction centrality measures per target for each drug that are calculated at the interaction centrality measure calculating step; and a rejection score outputting step of outputting, via the output unit, the rejection score that is calculated at the rejection score calculating step. 6. An approval prediction method executed by an approval prediction apparatus including an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that includes proteins having similarity; and a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; and the method executed by the control unit includes: a similarity centrality measure calculating step of, based on the similarity network information stored in the similarity network information storage unit, calculating similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an approval determining step of, based on the approval attributes of the drugs targeting the proteins according to the protein information stored in the drug target storage unit, which are the proteins that the protein similarity network includes, obtaining a determination result representing whether the proteins to be validated, which are proteins that the similarity network includes, are within a range of targets of approved drugs or a range of targets of rejected drugs, using the similarity centrality measures of the proteins to be validated that are calculated at the similarity centrality measure calculating step; and a determination result outputting step of outputting, via the output unit, the determination result that is obtained at the approval determining step. 7. A computer program product having a non-transitory tangible computer readable medium including programmed instructions for causing, when executed by an approval prediction apparatus including an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that is constructed according to the similarity between proteins; a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; and an interaction network information storage unit that stores interaction network information on a protein-protein interaction network that is constructed based on interactions between the proteins; the approval prediction apparatus to perform an approval prediction method comprising: a similarity centrality measure calculating step of, based on the similarity network information stored in the similarity network information storage unit, calculating similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an interaction centrality measure calculating step of, based on the interaction network information stored in the interaction network information storage unit, calculating interaction centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein-protein interaction network includes; a rejection score calculating step of calculating a rejection score that represents probability of a compound to be validated to be classified as a rejected drug, using classifiers that use, as training data, the approval attributes of the respective drugs stored in the drug target storage unit, the sum and average of the similarity centrality measures per target for each drug that are calculated at the similarity centrality measure calculating step, and the sum and average of the interaction centrality measures per target for each drug that are calculated at the interaction centrality measure calculating step; and a rejection score outputting step of outputting, via the output unit, the rejection score that is calculated at the rejection score calculating step. 8. A computer program product having a non-transitory tangible computer readable medium including programmed instructions for causing, when executed by an approval prediction apparatus including an output unit, a storage unit, and a control unit, wherein the storage unit includes: a similarity network information storage unit that stores similarity network information on a protein similarity network that includes proteins having similarity; and a drug target storage unit that stores drug information containing approval attributes of drugs on approval or rejection and protein information on the proteins targeted by the drugs in association with each other; the approval prediction apparatus to perform an approval prediction method comprising: a similarity centrality measure calculating step of, based on the similarity network information stored in the similarity network information storage unit, calculating similarity centrality measures that are centrality measures containing the degree centrality, betweenness centrality, closeness centrality, and Burt's constraint of the proteins that the protein similarity network includes; an approval determining step of, based on the approval attributes of the drugs targeting the proteins according to the protein information stored in the drug target storage unit, which are the proteins that the protein similarity network includes, obtaining a determination result representing whether the proteins to be validated, which are proteins that the similarity network includes, are within a range of targets of approved drugs or a range of targets of rejected drugs, using the similarity centrality measures of the proteins to be validated that are calculated at the similarity centrality measure calculating step; and a determination result outputting step of outputting, via the output unit, the determination result that is obtained at the approval determining step.