Making an impact is important when it comes to working in research, but judging the impact of research, publications and careers, for example, is not a straightforward process. Journals are currently ranked by the Thomson Reuters ISI impact factor, and the updated impact factors were released recently. Nature Reviews Cancer did well, for which we would like to thank all of our authors who wrote for the journal in 2008 and 2009, which are the years that count for the 2010 impact factor. Despite this 'success', we need to continue to make an impact, and the only way we can do that is to consistently commission the most insightful and timely reviews.

With this in mind, we are publishing six Reviews in this month's issue, all of which deal with cancer research challenges, both old and new. For example, on page 573, John Condeelis and colleagues discuss chemotaxis. This is not a new phenomenon in cancer research and is one that should be amenable to drug targeting. However, as both tumour and stromal cells respond to chemotactic signals, a clear understanding of the pathways involved in different tumour types is still needed. An update on another area of long-standing interest in cancer research, that of calcium mobilization, is provided on page 609 by Natalia Prevarskaya and colleagues, who elaborate on how changes in calcium levels can contribute to metastasis.

Both calcium signalling and chemotaxis could prove to be of relevance to the development of sarcomas, which is discussed on page 541 by Marc Ladanyi and colleagues. Sarcomas remain a difficult type of tumour to treat, and more information is required if we are to make an impact on this disease. After all, an impact that can be felt in the clinic is the only one that really counts.