Post-translational modifications (PTMs) are indispensable for regulating protein function, and because of this several PTMs have been scrutinized as potential biomarkers or therapeutic targets. For example, the RAS family of proto-oncogenes, which are discussed on page 761 by Dafna Bar-Sagi and colleagues, are subject to lipid modification, which is known as prenylation. Prenylation, in the form of farnesylation and geranylgeranylation, has long been considered a target for cancer therapy, as discussed on page 775 by Norbert Berndt, Andrew D. Hamilton and Saïd M. Sebti. However, as these authors discuss, inhibiting this process is more effective in some tumours than in others.

Protein ubiquitylation is another PTM that can be targeted to induce cancer cell death. As Shigetsugu Hatakeyama outlines on page 792, the tripartite motif (TRIM) protein family is one of the subfamilies of the RING type E3 ubiquitin ligases, but the potential function of TRIM proteins in tumorigenesis might not be solely due to their possession of a RING domain. Another E3 ligase that is becoming of interest to cancer researchers is parkin, a protein that is mutated in Parkinson's disease. Germline homozygous mutations in PARK2 are associated with early-onset Parkinson's disease, but somatic heterozygous mutation of PARK2 is found in some human tumours, as discussed on page 812 by Nicholas W. Wood and colleagues. Links between this neurodegenerative disease and cancer should provide much food for thought.

Finally, PTMs also have a part in promoting cancer awareness: the growth of facial hair for Movember, to increase public knowledge about male cancers, is reflected in this month's cover, and Movember of course follows hard on the heels of a month of pink ribbons for breast cancer awareness. PTMs are definitely a hot (pink) topic!