 1. Identification and validation of response-predictive genes. The normalized pre-treatment microarray data of the training set is retrieved from SMD for statistical analysis. The supervised analysis SAM Significance Analysis of Microarrays, two class unpaired is performed to identify genes whose expression is significantly different between responders and non-responders. Then a Leave-one-out cross-validated gene-expression predictor for the 2 response classes is devised by the PAM Predication Analysis of Microarrays method based on nearest shrunken centroids. The unsupervised clustering of the independent test set is performed using the predictive genes and the prediction accuracy is calculated. Quantitative real-time PCR is performed as further validation using the un-amplified RNA samples and Taqman gene expression assays Applied Biosciences. 