Personalized medicine in cancer: where are we today?

open access

Section: Making the most of targeted therapy

Another important lesson from the laboratory has come from the study of cancer evolution, which has been aided significantly by deep sequencing technologies such as NGS. Recent studies have reported high numbers of heterogeneous gain and loss mutations which can occur between primary and distant sites and within primary tumors which develop drug resistance, drastically altering the biology of the cancer [21,22]. Based on these findings it seems clear that for optimal personalized care there is a need for clinicians, where possible, to take repeat biopsies of resistant tumors or biopsies of distant metastatic sites when considering targeted therapies. In many cases the cancer biology will have substantially changed and treatment decisions made on baseline diagnostic biopsies may no longer be effective. Indeed, in terms of predicting drug response, one recent study demonstrated the added value of an early on-treatment biopsy over baseline alone in predicting response to endocrine therapy, as the expression changes of some genes on therapy were more informative than their initial levels [20]....