Functional viability profiles of breast cancer.

The design of targeted therapeutic strategies for cancer has been driven by the identification of tumor specific genetic changes. However, the large number of genetic alterations present in tumor cells means that it is difficult to discriminate between genes that are critical for maintenance of the disease state from those that are merely coincidental. Even when critical genes can be identified, directly targeting these is often challenging, meaning that alternative strategies such as exploiting synthetic lethality may be beneficial. To address these issues, we have carried out a functional genetic screen in over 30 commonly used models of breast cancer to identify genes that are critical for the growth of specific breast cancer subtypes. In particular, we describe potential new therapeutic targets for PTEN mutated cancers and for ER+ve breast cancers. We also show that large-scale functional profiling allows the classification of breast cancers into subgroups distinct from established subtypes.