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Fig. 2 | BMC Medical Genomics

Fig. 2

From: Unearthing new genomic markers of drug response by improved measurement of discriminative power

Fig. 2

Measuring the discriminative power of a genomic marker with φ and the chi-squared test. a Scatter plot showing the logIC50 of n = 284 cell lines screened against the marketed drug Dasatinib. The left boxplot shows BCR_ABL positive cell lines, whereas the boxplot on the right shows cell lines without this mutation (the median of each group appears as a black horizontal line within the boxplot). The red dotted line is the IC50 threshold, which is defined as the mean of both medians. b Contingency table showing the number of training set cell lines in each of the four non-overlapping categories (TP, FN, FP, TN), where positives are cell lines below the threshold in the case of a sensitising mutation (above the threshold if the mutation induces resistance). φ and χ2 are functions of these metrics and summarise binary classification performance, as further described in the Methods section. BCR_ABL is a very strong marker of Dasatinib sensitivity as shown in the scatter plot and highlighted by both statistical tests (PMANOVA = 1.4∙10− 10, Pχ2 = 6.4∙10− 28), offering unusually high discrimination between cell lines according to their relative drug sensitivity (φ = 0.65)

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