Sofia K. Gruvberger, Markus Ringnér, Patrik Edén, Åke Borg, Mårten Fernö, Carsten Peterson, and Paul S. Meltzer Expression Profiling to Predict Outcome in Breast Cancer: the Influence of Sample Selection Breast Cancer Research 5, 23-26 (2003) Abstract: Gene expression profiling of tumors using DNA microarrays is a promising method for predicting prognosis and treatment response in cancer patients. It was recently reported that expression profiles of sporadic breast cancers could be used to predict disease recurrence better than currently available clinical and histopathological prognostic factors. Having observed an overlap in those data between the genes that predict outcome and those that predict estrogen receptor alpha (ER) status, we examined their predictive power in an independent data set. We conclude that it may be important to define prognostic expression profiles separately for ER-positive and ER-negative tumors. LU TP 02-17