Before the Susan G. Komen Tissue Bank began collecting "normal" tissue from donors, researchers relied on tissue from a few sources to investigate changes in the breast that lead to cancer. These traditional sources of tissue are from women who undergo reduction mammaplasty; from women with benign breast disease; and, sometimes, from the tissue of women already diagnosed with breast cancer.
But scientists knew they needed a true control group, tissue from women who had had none of these, to really understand the microscopic changes in the breast that lead to disease.
For this study, they used tissue from the KTB as a control to see how the "histologic", or microscopic properties, compared to the tissue from those traditional sources. If normal tissue looked quite different from that of other sources, they may be able to use that information to figure out what causes normal tissue cells to change.