1. A method of identifying one or more prostate tissue samples in a database that are most similar to a test prostate sample, comprising: extracting at least 20 morphological features from the test prostate tissue sample; determining similarities based on the morphological features between the test prostate sample and a plurality of prostate tissue samples in a database; and retrieving from the database one or more prostate tissue samples in the database that are the most similar to the test prostate tissue sample.