Tailored therapies based upon tumor subtype biology

Excerpt

Breast cancer is a spectrum of diseases comprised of different tumor subtypes, each with a distinct biology and clinical behavior. To capture this diversify, we characterized the variation in gene expression across human breast tumors using DNA microarrays and identified at least five distinct tumor subtypes that are statistically significant predictors of patient overall survival [1]. Recently, we further validated these findings using a training set of 102 tumors, which was used to derive a new 'intrinsic gene set'. This gene set was then validated using a true test set of 311 tumors compiled from three different microarray studies. Our analyses demonstrate that common patterns of gene expression can be identified across different microarray platforms, that the breast tumor 'intrinsic' subtypes are reproducible across different datasets, and that this classification was a significant predictor of outcomes after correcting for standard clinical parameters such as estrogen receptor (ER), grade and node status [2]. …