Pattern of gene expression of genes used to determine the clinical characteristics of 24 FL samples (test series). (A) The expression data matrix of 18 tumor samples with an unclear morphology across the 81 gene profile. The genes in the horizontal direction are arrayed in the same order as in Figure 2B. Tumors are rank ordered according to the difference in correlation to the molecular high-grade and low-grade profile as in Figure 2 (middle panel). The yellow line is the threshold as determined in Figure 2B (see Figure 2 for color scheme). Morphologic data, IPI scores, and clinical behavior are shown on the right. □, , and ▪ are as indicated in Figure 1B. Of the 18 samples, the classifier predicted the actual clinical behavior correctly in 17 patients (accuracy 94%). (B) Expression data of 6 tumor samples from patients with unequivocal morphologic and clinical indolent disease, but who presented with full-blown aggressive disease within 10 months. One sample was classified as molecular high-grade.