Successful transformation of cryopreserved lymphocytes: a resource for epidemiological studies.

The Cooperative Family Registry for Breast Cancer Studies (CFRBCS) is an international multisite cooperative consortium of investigators who collaborate to ascertain families at risk for breast cancer. Sufficient blood was collected from each individual participating in the CFRBCS to permit the isolation of lymphocytes, distribution into four aliquots, and cryopreservation for future transformation. To determine the success rate for transformation of these cryopreserved lymphocytes and whether processing and cryopreservation of lymphocytes affected the length of time required to achieve a successful transformation, a study was initiated with cryopreserved samples from CFRBCS participants. To date, using EBV transformation protocols, noncontaminated, viable cell lines have been successfully established from lymphocytes cryopreserved from 124–678 days (mean 6 SE 5 418 6 6 days). Cryopreserved lymphocytes from these CFRBCS participants were successfully transformed within an average of 40.2 6 0.8 days (mean 6 SE). The time required for successful transformation for freshly isolated lymphocytes from the same study population was 35.2 6 0.3 days. Although the success rate for transformation was slightly less for the cryopreserved sample set (90% versus 94% for freshly isolated lymphocytes), the availability of multiple aliquots of cryopreserved lymphocytes from each registry participant for additional transformation attempts virtually guarantees the establishment of a cell line. Cryopreservation of isolated lymphocytes for future transformation represents an economical alternative to the establishment of cell lines at the time of venipuncture for epidemiological studies such as the CFRBCS that may require an unlimited source of genetic material for future studies.