Population Research Core

Population research core icon

Director: Brad McDowell, PhD
E226 GH

Faculty Advisors:

  • Mary Charlton, PhD
  • Michael O’Rorke, PhD
  • Mark Vander Weg, PhD

The Population Research Core (PopRC) is a centralized resource dedicated to the needs of the Holden Comprehensive Cancer Center (HCCC) in the domain of population science. We provide high quality epidemiology support that promotes strong observational study designs and methodology. The PopRC provides this support in close collaboration with HCCC members and the Tissue Procurement Core, the Molecular Epidemiology Resources, and the Biostatistics Core.

The primary resources of the PopRC are the expertise and time of its scientific personnel. Staff members possess extensive expertise in the use of various population-based resources.

The core provides the following services:

Study design and methodology

PopRC works with users to develop study design and methodology to answer population-based research questions. This includes planning comparisons and selection of appropriate epidemiological study designs (e.g., retrospective cohort study, case-control, etc.). PopRC also identifies the methodological resources that will be used to accomplish study goals.

Database research activities

PopRC staff members are familiar with commonly used datasets (e.g., the unlinked SEER research database, SEER-Medicare, and Iowa cancer incidence and follow-up data) along with many others. They work with investigators to develop inclusion and exclusion criteria; determine definitions for cohort initiation, follow-up, and censoring; construct and validate analytic variables; perform database linkages; maintain quality control; and develop database queries.

Population-based field research

Other population-based studies require prospective collection of data or coding of existing information. In these cases, PopRC staff can apply field research techniques. PopRC staff and faculty advisors have extensive experience and support tools for recruitment/consenting of study participants, administering surveys/interviews, development of cohort selection criteria, medical chart abstraction, and participation monitoring/study management.


The Iowa Cancer Registry has worked with pathology labs around the state for more than three decades to retrieve formalin-fixed paraffin-embedded tissue for research studies. This constitutes a virtual repository (VTR) of tissue samples that are linked with cancer incidence and follow-up data (which includes demographic, tumor, initial treatment, and outcome data). In addition to this resource, the Iowa Cancer Registry has worked with the same pathology labs to retrieve and store older paraffin-embedded tissue blocks that these labs would have otherwise destroyed. These samples compose a residual tissue repository (RTR) that also is linked to cancer surveillance data. The Holden Comprehensive Cancer Center’s Tissue Procurement Core (TPC) works closely with PopRC to encourage use of this unique resource. More information on this tissue resource.