June 4th 2009With the FDA approval of a new small-molecule drug to treat HIV infection by blocking the CCR5 chemokine receptor and with several other drugs of this class in development for this and other indications, there is an increased interest in determining the potential influence on tumor promotion or suppression that blocking this receptor may have. Large, long-term clinical studies would be the ideal method for evaluating the potential increase in cancer risk, and at least one such study is under way (see http://clinicaltrials.gov/show/NCT00665561?order=49).