Comparison of IGV with Intra-Tumour Heterogeneity.

<p>(a) Cross-sample variability of methylation (Intra-tumour heterogeneity) and IGV are calculated in different and complementary directions. The heatmap displays the methylation profile of a single gene (horizontal axis), across multiple samples (vertical axis). (b)-(e) A characteristic pattern of high cross-sample variability (intra-tumour heterogeneity) when IGV is low, and vice-versa, is consistently observed across different studies: (b) Main OC data-set, (c) Endometrial cancer intra-tumour heterogeneity data-set, (d) prostate cancer intra-tumour heterogeneity data-set, (e) BRCA basal data-set. (f)-(h) The overlap of genes in each region of (b) with genes in equivalent regions of (c)-(e) is highly significant. In (c) and (d), each line relates to samples from a single patient, and is a best fit curve equivalent to that shown in (b) and (e). In (b), odds-ratios and <i>p</i>-values at the top of the plot show enrichment of the genes of each cluster, either side of the median IGV of the prognostic signature. Abbreviations: ITH (intra-tumour heterogeneity), OC (ovarian carcinoma), BRCA (breast cancer invasive carcinoma).