Study to evaluate the effect of intratumoral heterogeneity on gene expression measurements

To evaluate the effect of intratumorally heterogeneity on gene expression measurements, we profiled and compared samples from different macroscopic tumor areas. Information was used to select probe sets with a high spatial reproducibility for the development of gene signatures. Samples were taken from three macroscopic tumor areas from 51 surgical breast cancer specimens prior to any systemic treatment. Samples were profiled on Affymetrix U133A microarrays to evaluate the reproducibility of each probeset.