Dr Pusztai is Professor of Medicine at Yale University, Scientific Co-Director of the Center for Breast Cancer at Yale Cancer Center and Co-Leader of the Yale Cancer Center Genomics Genetics and Epigenetics Program. His research group has made important contributions to establish that estrogen receptor-positive and-negative breast cancers have fundamentally different molecular, clinical and epidemiological characteristics. He has been a pioneer in evaluating gene expression profiling as a diagnostic technology to predict chemotherapy and endocrine therapy sensitivity and have shown that different biological processes are involved in determining the prognosis and treatment response in different breast cancer subtypes.