Validation results for the optimal combination rules.

<p>Validation of the three selected secondary data sources and the best performing combination rules on six new microarray data sets, referred to as V1 to V6. Per validation data set, five bars with the average test AUC under best training are shown: 1) mean AUC of the baseline model (blue); 2) mean AUC for the best individual secondary data source (KEGG, OPHID or microRNA.org) (cyan); 3) mean AUC for the fixed mean rule (green); 4) mean AUC for the weighted combination rule (orange); 5) mean AUC for the naïve Bayes rule (brown). A numerical overview is given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0010225#pone-0010225-t006" target="_blank">Table 6</a>.