The use of restriction fragment polymorphisms to identify the cell line MCF-7.

We have recently documented variations in the level of N-ras gene amplification in independently passaged MCF-7 cells. To establish if these differences are due to a lack of genetic identity between current MCF-7 passages and the original cell line, we have performed karyological and restriction fragment length polymorphism (RFLP) analyses. Documentation of a combination of restriction fragment patterns which are characteristic of MCF-7 has been facilitated by an analysis of DNA from an early-passage of MCF-7 from the Michigan Cancer Foundation (MCF). In addition, such early passage cells and other MCF-7 lines also share a unique amplification of the N-ras oncogene. Using these criteria and karyotypic analysis it can be shown that a sample of MCF-7 obtained from the American Type Culture Collection (ATCC) was derived from a different individual than was the original MCF-7 cell line. It is important that researchers verify the relationship of current cell lines to the original MCF-7. Furthermore, the techniques described here provide a powerful tool which may be used to assess the identity of cell stocks.