Inclusion of biospecimens in population-based studies is an integral part of understanding
disease etiology, identifying biomarkers and developing prevention and treatment strategies. The Prostate,
Lung, Colorectal, and Ovarian (PLCO) cancer screening trial collected, processed and stored
biospecimens from participants to create a biorepository of specimens which serves as a useful resource
for a broad research community. PLCO collected blood samples from consented screening arm participants at six
screening rounds and a buccal sample from consented control arm participants. In addition, formalin-fixed paraffin embedded
tumor tissue specimens were collected for participants in both arms for selected cancer sites. Collection of biospecimens
at multiple timepoints (i.e. serial samples) and prior to cancer diagnosis, paired with rich epidemiologic and
screening data, makes the PLCO collection of biospecimens a uniquely valuable resource. As such, access to the PLCO
biorepository is granted to investigators by a rigorous scientific review process and guided by a steering committee which
is responsible for developing and implementing the biospecimen use policies. Here, we describe the procedures for biospecimen
collection, processing, storage, requisition, and distribution, as well as data management employed in PLCO.
We also provide examples of how the biospecimens have been used to advance cancer research and describe relevant lessons
learned to help inform cohorts wishing to add or modify biospecimen collection.