A comparison of gene expression signatures from breast tumors and breast tissue derived cell lines

Cell lines derived from human tumors have historically served as the primar y experimental model system for exploration of tumor cell biology and pharm acology. Cell line studies, however, must be interpreted in the context of artifacts introduced by selection and establishment of cell lines in vitro. This complication has led to difficulty in the extrapolation of biology ob served in cell lines to tumor biology in vivo. Modern genomic analysis tool like DNA microarrays and gene expression profiling now provide a platform for the systematic characterization and classification of both cell lines a nd tumor samples. Studies using clinical samples have begun to identify cla sses of tumors that appear both biologically and clinically unique as infer red from their distinctive patterns of expressed genes. In this review, we explore the relationships between patterns of gene expression in breast tum or derived cell lines to those from clinical tumor specimens. This analysis demonstrates that cell lines and tumor samples have distinctive gene expre ssion patterns in common and underscores the need for careful assessment of the appropriateness of any given cell line as a model for a given tumor su btype.