Supervised classification of cHL samples based on the “clinical outcome” signature and on the “EBV status” signature. (A) The classification of 52 informative cHL adult samples using the molecular signature of 501 probe sets correlated with clinical outcome. Thirty-one samples were from patients with favorable outcome (FO) and 21 samples from patients with unfavorable outcome (UO). Expression data and clinical features (top panel) are depicted as in Figure 1. Probe sets are ordered from top to bottom by their decreasing discriminating score. Tumor samples are ordered from left to right according to their LDA function score. The solid orange line indicates the threshold 0 that separates the 2 predicted classes of samples referred to as “predicted FO group” (at the left of the line) and “predicted UO group” (right to the line). The bottom panel represents the LDA posterior probability for each sample to belong to the FO group (y-axis), with the samples (x-axis) ranked according to their LDA function score. The observed clinical outcome is indicated by colored dots: green indicates FO; red, UO. There was a statistically significant correlation between the observed clinical outcome and the predicted clinical outcome based on the corresponding gene signature, as shown by the resulting cross table. With a representation similar to panel A, panel B shows the molecular classification of 53 informative cHL samples using the 425 probe sets identified as differentially expressed between the 18 EBV⁺ samples and the 35 EBV⁻ samples (top panel). The LDA posterior probability (y-axis) is the probability for each sample to belong to the EBV⁻ group (bottom panel). The observed EBV status is indicated by colored dots: green indicates negative; red, positive. The statistical correlation between the observed EBV status and the predicted EBV status was highly significant, as shown by the resulting cross table.