Across the world, freezers and cabinet shelves are full of human samples.
Biobanks — collections of biological material set aside for research — vary tremendously in size, scope and focus. Samples can be collected from the general population, from patients who have had surgery or a biopsy and from people who have recently died. Some collections date back decades. The Aboriginal genome, for instance, was sequenced from a lock of hair originally given to British ethnologist Alfred Cort Haddon in the 1920s; he crisscrossed the world gathering samples that are now housed at the University of Cambridge, UK. Most collections contain dried or frozen blood, but tissues such as eye, brain and nail are also held. Some biobanks address different questions from others: a population-based biobank that collects dried blood and health data may be used to determine the genetic risk factors for breast cancer, whereas a disease biobank that collects tumour samples might be used to reveal different molecular forms of breast cancer.
The number of tissue samples in US banks alone was estimated at more than 300 million at the turn of the century and is increasing by 20 million a year, according to a report1 from the research organization RAND Corporation in Santa Monica, California. Those numbers are probably an underestimate, says Allison Hubel, director of the Biopreservation Core Resource at the University of Minnesota in Minneapolis.