Example of a pure sponge module. A) A prototype of pure sponge module extracted from the normal MMI-network. B-C) Scatter plots of expression profiles in normal and cancer dataset, respectively. Plots are shown for, from left to right: PTENP1 versus HRASL5, mir-135b versus HRASL5, mir-135b versus PTENP1. y- and x-axis: normalized read counts from TCGA (log2-scale); r = Pearson correlation coefficient, p = p-values. Correlations and p-values are computed by using the routine corr of MATLAB. Each p-value is the probability of getting a correlation as large as the observed value by random chance, when the true correlation is zero.