Artem Baranovsky, Timofei Ivanov, Dmitri Papatsenko and Dmitri Pervouchine from Skoltech have published a preprint “Transcriptome analysis reveals high tumor heterogeneity with respect to re-activation of stemness and proliferation programs” at bioRxiv. In many malignant tumors, some cells switch to a stemness-related gene program, which is normally active only in embryonic stem cells. In this work, the researchers used RNA-seq data from The Cancer Genome Atlas (TCGA) Consortium to study the expression of stemness-related and proliferation-related genes across a collection of different tumor types. The researchers have introduced a metric that captures the collective similarity of the expression profile of a tumor to that of embryonic stem cells, which showed that stemness and proliferation signatures vary greatly between different tumor types. They also observed a high degree of intertumoral heterogeneity in the expression of stemness- and proliferation-related genes. Taken together, the results indicate that the expression of stemness signatures is highly heterogeneous and cannot be used as a universal determinant of cancer. Full text of the preprint is available here.