Surgically removed lymphatic tissue, bone marrow biopsy, or other tissue that is suspected to have a hematologic malignancy should be placed in a sterile. leak-proof transport container which contains a small amount of sterile RPMI-1640 tissue culture medium sufficient to cover the tissue. This medium is commercially available from a number of sources, including Sigma Chemical Company, Irvine Scientific Company, and Gibco. This medium should be clear pink or magenta. If the RPMI-1640 turns yellow or cloudy, it should be discarded. DO NOT FREEZE the tissue, fix the tissue, or allow the tissue to dry out at any time. Alternatively, wrap the tissue in a saline-soaked gauze and place in a sterile container. It should be noted that this alternative procedure for shipping tissue may result in decreased viability, especially in high grade lymphomas. The size of the tissue sample required for an adequate cell yield depends on a variety of factors. In general, a sample of at least 3 millimeters in diameter is needed (small pea sized is preferred). In some cases, an adequate cell yield can be obtained from even smaller samples or even needle aspirates. The sample should be stored and shipped at 4°C or at room temperature.