1. A disease analysis apparatus comprising a memory storing instructions and a processor configured to execute the instructions to: acquire an analysis image that is an image in which a plurality of cell nuclei in a lesion of a target person are captured; calculate a feature-value relating to the cell nuclei using the analysis image; acquire an evaluation function from the memory; generate prediction information relating to the target person, based on the feature-value calculated from the analysis image, and based on the evaluation function, the prediction information indicating a prediction relating to a prognosis of a disease or a prediction relating to malignancy of a disease; determine a plurality of target regions from the analysis image by: generating the prediction information for each of the plurality of cell nuclei based on the feature-value calculated for each of the plurality of cell nuclei and the acquired evaluation function, determining the prediction information indicating a possibility of recurrence of a disease or high malignancy of a disease, among the generated prediction information, and determining a region in the analysis image as one of the plurality of target regions, the determined region including the cell nuclei for which the determined prediction information is generated; calculate the feature-value relating to each target region; generate the prediction information for each target region based on the feature-value relating the target region and the acquired evaluation function; and perform a statistical process on the prediction information generated for each target region, thereby generating statistical prediction information relating to the target person.