Expression profiling predicts outcome in breast cancer

Gruvberger et al. postulate, in their commentary published this issue of Breast Cancer Research, that our “prognostic gene set may not be broadly applicable to breast tumor cohorts”, and they suggest that “it may important to define prognostic expression profiles separately estrogen receptor (ER) positive and negative ”. This is based on two observations derived from gene expression profiling data in breast cancer: the between reporter genes for prognosis and ER , and Gruvberger et al.’s inability to confirm the prediction using a nonoptimal selection of 58 of 231 prognosis reporter genes.