These are calcium deposits, often found in clusters by a mammogram. These deposits, sometimes called calcifications, are neither cancer nor tumors. But there are signs of changes within the breast, often merely due to aging, and they are very common. Because certain patterns of calcifications can be associated with cancer or benign breast disease, they should be monitored. Follow-up may be either by periodic mammography or by biopsy, a procedure in which a sample of the breast tissue containing the calcium deposit is taken to test for cancer cells.