Mechanisms that Impact Cancer Risk after Bariatric Surgery (R21 Clinical Trial Not Allowed) | PAR 21 332

Opportunity Information: Apply for PAR 21 332

The National Cancer Institute (NCI) is offering this R21 funding opportunity, titled "Mechanisms that Impact Cancer Risk after Bariatric Surgery (R21 Clinical Trial Not Allowed)" (PAR-21-332), to support early-stage, investigator-initiated research focused specifically on how bariatric surgery may change a persons risk of developing cancer. The program is designed to pull attention beyond the more commonly studied short-term outcomes of bariatric procedures, such as weight loss and improved diabetes control, and instead push the field toward understanding the biological, behavioral, and physiological mechanisms that might explain observed differences in cancer risk after surgery. The emphasis is on mechanistic insight and hypothesis exploration rather than definitive, late-stage confirmation studies.

This FOA uses the NIH R21 mechanism, meaning it is intended for proof-of-concept, feasibility, and exploratory developmental work. The goal is to help researchers test new ideas, generate foundational evidence, and establish whether a novel mechanistic question can be studied rigorously before moving to a larger, more definitive project (often an R01). A key point in this announcement is that the feasibility angle should be genuinely exploratory: applicants should not propose work where feasibility has already been established in the published literature or supported by existing preliminary data. In other words, NCI is trying to fund high-potential, early ideas that still need an initial demonstration of practicality or tractability.

The FOA also draws a hard line around preliminary data expectations and what can be cited. Unpublished data are not permitted for supporting the application under this R21 concept, which is somewhat unusual compared with many NIH applications where preliminary results often appear. However, the announcement allows applicants to cite and reference widely available preprints as long as those preprints have a Digital Object Identifier (DOI). This creates a pathway for applicants to ground their ideas in accessible evidence while maintaining the programs intent to avoid proposals that already have substantial unpublished internal feasibility work. Investigators who already have unpublished preliminary findings in hand are directed to pursue the companion R01 instead, signaling that the R21 is meant for earlier-stage exploration, while the R01 is meant for more developed projects.

This opportunity is explicitly "Clinical Trial Not Allowed," meaning applicants cannot propose a study that meets the NIH definition of a clinical trial (for example, prospectively assigning human participants to interventions to evaluate health-related outcomes). Applicants can still propose human subjects research if it is observational or otherwise does not meet the clinical trial definition, and they can propose mechanistic work using biospecimens, existing cohorts, secondary data analyses, animal models, or laboratory-based studies that help explain how bariatric surgery might influence cancer-related pathways. The central requirement is that the work should illuminate mechanisms linking bariatric surgery to cancer risk, rather than focusing on endpoints like pounds lost, short-term metabolic markers alone, or diabetes remission without a clear tie to cancer biology or cancer risk pathways.

Eligibility is broad, reflecting NIH norms and NCI interest in bringing diverse institutions into this research space. Eligible applicants include state, county, city, and special district governments; federally recognized tribal governments; tribal organizations (including those other than federally recognized tribal governments); public housing authorities/Indian housing authorities; independent school districts; public and state-controlled institutions of higher education; private institutions of higher education; nonprofits with and without 501(c)(3) status; for-profit organizations (other than small businesses); small businesses; and other organizations. The FOA also highlights additional categories such as Historically Black Colleges and Universities (HBCUs), Hispanic-serving Institutions, Tribally Controlled Colleges and Universities (TCCUs), Alaska Native and Native Hawaiian Serving Institutions, and Asian American Native American Pacific Islander Serving Institutions (AANAPISIs), as well as faith-based or community-based organizations and eligible federal agencies, underscoring an intent to broaden participation across different research and community settings.

At the same time, there are important limits on foreign involvement. Non-domestic (non-U.S.) entities and non-domestic foreign institutions are not eligible to apply as the applicant organization, and non-domestic components of U.S. organizations are also not eligible to apply. However, "foreign components" are allowed as defined by the NIH Grants Policy Statement, meaning a U.S. applicant may include certain kinds of substantive project activities performed at a foreign site if they are appropriately justified and structured under NIH rules. This distinction matters for teams that might want to incorporate international expertise, datasets, or laboratory capabilities without having a foreign institution serve as the primary applicant.

Administratively, the opportunity is run by the National Institutes of Health (NIH) under NCI and is categorized as a discretionary grant program in the broad area of education and health. It is associated with CFDA numbers 93.393, 93.396, and 93.399. The FOA record indicates an original closing date of 2024-09-07 and a creation date of 2021-09-03. The listing does not specify an award ceiling or expected number of awards in the provided text, so applicants would need to consult the full FOA for budget guidance, project period expectations, and submission details typical of NIH R21 announcements.

In practical terms, the ideal application under this FOA proposes a creative, mechanistically driven question about how bariatric surgery could plausibly reduce or alter cancer risk, paired with a study design that can demonstrate feasibility and generate early evidence without relying on proprietary unpublished preliminary data. Strong proposals would make a clear case for why the mechanistic pathway is important for cancer prevention or cancer etiology, why bariatric surgery provides a useful context to probe that pathway, and how the exploratory work could set up a larger, more definitive follow-on project if the proof-of-concept results are promising.

• The National Institutes of Health in the education, health sector is offering a public funding opportunity titled "Mechanisms that Impact Cancer Risk after Bariatric Surgery (R21 Clinical Trial Not Allowed)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.393, 93.396, 93.399.
• This funding opportunity was created on 2021-09-03.
• Applicants must submit their applications by 2024-09-07. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Eligible applicants include: State governments, County governments, City or township governments, Special district governments, Independent school districts, Public and State controlled institutions of higher education, Native American tribal governments (Federally recognized), Public housing authorities/Indian housing authorities, Native American tribal organizations (other than Federally recognized tribal governments), Nonprofits having a 501 (c) (3) status with the IRS, other than institutions of higher education, Nonprofits that do not have a 501 (c) (3) status with the IRS, other than institutions of higher education, Private institutions of higher education, For-profit organizations other than small businesses, Small businesses, Others.

Apply for PAR 21 332

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