Figure 2

Generation and validation of the mouse mammary tumor signature. We generated a mouse mammary tumor predictor based on gene expression of PBCs from a training set of tumor-bearing transgenic mice (n = 32) and nontransgenic tumor-free mice (n = 14). (A) This signature is capable of distinguishing the two classes accurately within the traning data set as shown in the model fit diagram. Blue = healthy tumor-free control mice; red = MMTV/c-MYC tumor-bearing mice. (B) Furthermore, this signature was applied to an independent set of PBC samples from transgenic tumor mice (n = 33) and nontransgenic controls (n = 14) to predict the tumor status of each sample. It demonstrated 100% sensitivity and 100% specificity in predicting tumor status, using the optimal threshold of 0.8118 as calculated using Youden's J-statistic.