Among the 10 genes in the classifier, COL4A1 was significantly higher in low LumE tumors and, because of the availability of good antibodies for IHC, was selected for further orthogonal validation in an independent set of hormone-naïve primary prostate tumors (n = 46) with clinical and follow-up data (Figure 6A). This evidence concerns the gene COL4A1 and prostate neoplasm.