Alternatively, intratumour metabolic heterogeneity can be roughly inferred through transcriptional heterogeneity: the putative tumour suppressor ISL2 is epigenetically silenced in only some regions of human PDAC tumours, and ISL2 downregulation leads to enhanced expression of genes involved in oxidative phosphorylation, thus potentially rendering those cells sensitive to mitochondrial electron transport chain inhibitors [106]. This evidence concerns the gene ISL2 and neoplasm.