As part of the research, investigators often wish to have part of the tumour tissue already obtained at surgery sent to a tumour or tissue bank for extra tests that may help scientists and physicians learn more about the cancer cells and their behaviour or molecular features. Less commonly, they may wish to repeat a biopsy of a cancer that has already been diagnosed. Usually, if there is a wish to obtain any additional fresh tissue for extra tests, that is an optional part of the study, and a patient is able to participate in the trial, but decline the extra biopsy.

Sometimes there are specific tests that scientists wish to do as part of the study. For example, the scientists may wish to test for the presence of a particular abnormal protein or receptor in the cancer cells of each patient, to try to find out whether this will correlate with how the cancer cells respond to treatment. Other times, there aren't any immediate tests to be done, but tests may be developed in future that would be of great interest. If the study involves banking of tumour tissue, blood, or any other human tissue, for future testing, patients will be given a second informed consent form to sign, to indicate whether they do or do not give their permission for tissue to be banked. This is usually a much shorter consent form (2-4 pages), and explains what will be done with the specimen, and whether any information from testing will ever be relayed back to the patient or their physician. In most cases, there is no plan to communicate information back to the individual person.