Population analysis for receptor status. Population analysis for (a) oestrogen receptor (ER) status. Using the transcript signature from the ANN model, it is possible to be able to place a patient with unknown ER status within this population structure, with 100% accuracy from an ANN prediction, (b) progesterone receptor (PR) status, and (c) HER2/neu status. White, receptor-negative patients; grey, receptor-positive patients. y axis, artificial neural network (ANN) prediction with 0 being a receptor-negative prediction and 1 a receptor-positive prediction. Error bars indicate a 95% confidence interval.