As one door closes, another opens, and so it is with two of our Article Series this month. The Review on page page 785 by Hui-Zi Chen, Shih-Yin Tsai and Gustavo Leone is the last in our short series on RB and E2F. In this Review, the authors highlight functions of the E2F family of transcription factors that are not involved in the regulation of the cell cycle, for which the RB–E2F pathway is best known. How these findings will influence cancer research in the future is not yet clear and further work is therefore essential. Overall, the four articles that make up the RB and E2F series have highlighted how this field has progressed from one that was cell cycle-centric to one that now encompasses many aspects of cancer cell biology.

Our new Article Series launching this month is on a much broader topic: the epigenetics and genetics of cancer. This is an essential area of cancer research with many potential therapeutic implications, such as personalized medicine, but more basic biological knowledge is needed to effectively bring new treatments based on genetic and epigenetic changes into the clinic. Our understanding of the mechanisms through which genetic and epigenetic changes occur and the resulting effects on tumour biology and clinical outcome is increasing rapidly. The first article in this Series (on page 773), by Adrian P. Bracken and Kristian Helin, focuses on the polycomb group (PcG) proteins. These transcriptional repressors regulate lineage choices during development and differentiation, and this Review discusses the emerging mechanisms by which long non-coding RNAs and subsets of 'cell fate transcription factors' regulate PcGs and how their coordinated deregulation contributes to tumorigenesis. Future articles on the epigenetics and genetics of cancer will appear on our Series landing page: http://www.nature.com/nrc/series/epigenetics.