In fact, increasing numbers of genes and gene products are claimed to have prognostic relevance for many types of tumors, with varying degrees of evidence supporting these contentions, and a panoply of different experimental approaches and study populations. Distilling coherent recommendations from this data has been approached, in the case of HER2 testing in breast cancer, through focused analysis by a multidisciplinary consensus panel.4 The NCCN HER2 Testing in Breast Cancer Task Force convened recently to critically evaluate the ability of the level of HER2 expression or gene amplification in breast tumors to serve as a prognostic and a predictive factor in metastatic and adjuvant settings, to assess the reliability of the methods of measuring HER2 expression or gene amplification in the laboratory, and to make recommendations regarding the interpretation of test results, which will be widely adopted. The expansion of data on prognostic markers has also been accompanied by the appearance of personalized tumor testing for genes and gene products predictive of responsiveness to specific therapeutic agents.,10–12 Although substantial outcomes-based research is needed to substantiate the prognostic relevance of some of the putatively important genes or gene products, these molecular profiling approaches have the potential to sort the patients likely to benefit from specific agents, from those who are unlikely to respond, and for whom the morbidity and mortality risks associated with therapy may not be warranted. Robust and well validated testing systems are a precondition for the clinical trials that will follow to determine the linkages between disease process, genomic or proteomic characteristic, specific therapeutic agent, and therapeutic response. Testing paradigms like those employed by Horiike and colleagues, which utilize innovative new technologies to maximize the information gained from small samples, are well worth a look.