Molecular characterization of tumor cells from the cerebrospinal fluid and matched primary tumors from metastatic breast cancer patients with leptomeningeal disease

We purified tumor cells in the CSF (“CSFTC”) from 15 metastatic breast cancer patients diagnosed with leptomeningeal disease using a two-step method involving immunomagnetic enrichment and fluorescence-activated cell sorting (IE/FACS). Magnetic beads coated with mAb to the epithelial cell adhesion marker (EPCAM) were used to enrich for tumor cells and were further purified by FACS analysis. For DNA profiling, isolated CSFTC were subjected to molecular characterization through genome-wide copy number analyses. Genomic analyses were then compared with those performed on the corresponding archival primary tumors. For RNA profiling, isolated CSFTC were then subjected to molecular characterization through gene expression profiling via QPCR analysis of 64 cancer-related genes CGH: 17 CSFTC samples from 13 patients were successfully profiled ,1 patient had 5 timepoints, 6 of 13 patients had matched to copy number data archival tumors RNA: 18 samples from 5 patients had successful gene expression data of the 64 genes measured in triplicates. For non-tumor controls, 9 of the samples had matching gene expression data from sorted leuckocytes (+CD45 cells) obtained from the same draw.