Dear Researchers,

As the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial nears the close of its active follow-up phase, we are writing to share important updates regarding the future of the samples in the PLCO biorepository and to notify you of a research opportunity involving PLCO samples.

PLCO currently holds approximately 3.4 million biospecimen vials (0.2 to 1.8 ml), representing one of the most deeply characterized population-based resources available for cancer research. However, as we plan for the long-term sustainability of this resource, we must reduce the volume of specimens stored. This culling effort is essential to manage rising storage costs and to free up freezer space for samples from new and ongoing NCI-supported studies.

Culling Overview

Our goal is to reduce the biorepository to approximately 1.9 million vials by Spring 2026. This will be achieved through two types of removals: 1. Samples with quality or consent-related problems will be discarded outright. These include broken or contaminated vials, samples with missing or invalid participant identifiers, and specimens collected without adequate consent. 2. Excess samples that are scientifically usable but unlikely to be needed in the future will also be removed. These include multiple vials of the same material type from participants who did not develop cancer during follow-up.

Repurposing Opportunity

Importantly, these “excess” samples will be made available to the scientific community for repurposing. All repurposed samples will be from PLCO participants who did not develop cancer during follow-up, except for red blood cells and whole blood samples collected at year 3, for which case samples will be available. The following sample types will be repurposed: • Red blood cells (multiple timepoints): ~161,000 vials • Whole blood (T3, cases and non-cases): ~360,000 vials • Buffy coat: ~51,000 vials • Serum (multiple timepoints, including zinc-free serum): ~155,000 vials • Plasma (multiple timepoints, Sodium heparin and EDTA): ~210,000 vials

Demographic and clinical data associated with the samples will be available for download or upon request via a data only request process. Details are available on the Cancer Data Access System (CDAS) PLCO website at https://cdas.cancer.gov/plco/.

Proposal Submission and Eligibility Criteria

Researchers interested in applying for these samples should prepare a brief description of the sample types requested and the intended purpose of the request. This proposal should be submitted through the PLCO website (https://cdas.cancer.gov/learn/plco/instructions/?type=eems) and given a title that starts with the term “Repurposing:”.

To ensure scientific value and operational feasibility, we will prioritize sample repurposing proposals that meet the following criteria: • Submitted by a credible investigator or research group • Include a minimum request of 2,000 samples (larger requests encouraged) • Have simple or no matching criteria • Demonstrate capacity to receive and store biospecimens • Commit to receiving samples by Spring 2026 • Provide a short scientific justification for sample use

If the proposal is approved, NCI will cover costs associated with pulling and shipping samples and will initiate a material transfer agreement (MTA).

If you have questions about the proposal process, you can submit your inquiries through the CDAS website (https://cdas.cancer.gov/) using the “contact us” link. Please select “PLCO” then “Biospecimen availability” from the subject and topic dropdowns and note that you are asking about “Repurposing” in the first sentence of your message.

Timeline

Proposal submissions will be accepted through December 2025, with final decisions made in January 2026. Sample pulls and shipments will occur in the Spring of 2026.

We recognize the extraordinary contributions of PLCO participants and are committed to maximizing the long-term value of their donated specimens. We hope this repurposing initiative will enable a new wave of discovery built on the foundation PLCO has laid.

Requests for Preliminary Applications will only be accepted until August 15, 2025. If you plan to submit an EEMS application this cycle, an EEMS Preliminary Application is required. Once your Preliminary Application has been approved, you will receive a notification you can upload your Full Application.

The full application deadline is October 3, 2025.

We anticipate decision letters going out the end of December 2025 or early January 2026.

Information is available regarding the PLCO trial and PLCO biospecimens.

Please visit the EEMS Preliminary Application page to preview instructions about the process, review the Policies and Procedures, and begin a Preliminary Application.

If you have any questions, please contact CDAS staff at cdas-eems@imsweb.com.

Requests for Specimen Verification will only be accepted from Aug 10, 2025 to Sept 10, 2025. If you plan to submit a grant application this cycle, an approved Request for Specimen Verification is required. Once your Request for Specimen Verification has been approved, you will receive a confirmation letter to accompany your grant application.

The grant application deadline is October 10, 2025.

Information is available regarding the PLCO trial and PLCO biospecimens.

Please visit the PAR Request Form for Specimen Verification page to preview instructions about the process, review the Policies and Procedures, and begin a Request for Specimen Verification.

If you have any questions, please contact CDAS staff at cdas-eems@imsweb.com.

Requests for Specimen Verification will only be accepted from Apr 10, 2025 to May 12, 2025. If you plan to submit a grant application this cycle, an approved Request for Specimen Verification is required. Once your Request for Specimen Verification has been approved, you will receive a confirmation letter to accompany your grant application.

The grant application deadline is June 10, 2025.

Information is available regarding the PLCO trial and PLCO biospecimens.

Please visit the PAR Request Form for Specimen Verification page to preview instructions about the process, review the Policies and Procedures, and begin a Request for Specimen Verification.

If you have any questions, please contact CDAS staff at cdas-eems@imsweb.com.

Requests for Preliminary Applications will only be accepted until February 18, 2025. If you plan to submit an EEMS application this cycle, an EEMS Preliminary Application is required. Once your Preliminary Application has been approved, you will receive a notification you can upload your Full Application.

The full application deadline is April 1, 2025.

We anticipate decision letters going out the end of June/early July 2025.

Information is available regarding the PLCO trial and PLCO biospecimens.

Please visit the EEMS Preliminary Application page to preview instructions about the process, review the Policies and Procedures, and begin a Preliminary Application.

If you have any questions, please contact CDAS staff at cdas-eems@imsweb.com.