PIDs and cancer: an evolving story

Analysis of overall and site-specific cancer risk in patients with primary immunodeficiency diseases (PIDs) may shed light on the role played by the immune system in controlling malignancies. The association of PID and cancer has been known for many years. 1 However, until recently, data on cancer risk in patients with PID have mostly derived from volunteer reporting to PID registries 1-3 or from single-center studies. In this issue of Blood, Vajdic et al report on 1132 patients with PID whose data were entered into the Australasian Society of Clinical Immunology and Allergy (ASCIA) PID Registry and matched with those of the Australian National Death Index and of the Australian National Cancer Database. Because registration of primary invasive cancers is mandatory in Australia, the study by Vajdic et al represents the first large populationbased analysis of cancer risk in PID, relative to the general population.