Measurement of Micronucleus Incidence

Contract Period: From contract award until March 31, 2026 with two (2) one year option periods.

1. TITLE Measurement of Micronucleus Incidence in Urothelial and Buccal Epithelial Cells Collected from Wildland Firefighters

2. SCOPE 2.1. Introduction Firefighters have an increased risk of chronic cardiovascular diseases, respiratory diseases, and cancer. In 2024, the Government of Canada passed the Prevention and Treatment of Cancers Linked to Firefighting Act; one of the objectives is the establishment of a national framework whereby awareness about cancers linked to firefighter is increased. Early biomarkers of genotoxic effects, such as micronucleus (MN) incidence in targeted cell populations, can be used to monitor cancer risk (Fenech et al., 2020). More specifically, the presence of MN in bladder urothelial cells has been empirically and mechanistically linked to cancer (Arora et al., 2010; Espinoza et al., 2019). Similarly, MN in buccal (oral) epithelial cells have also been linked to an increased risk of cancer (Bolognesi et al., 2015). Health Canada (HC) is seeking a contractor to measure the incidence of MN in urothelial cells and buccal epithelial cells collected from wildland firefighters. The work is part of the deliverables outlined in an HC project entitled Genotoxic Effects as Early Biomarkers of Cancer Risk in Wildland Firefighters. The project is funded under the aforementioned national framework on cancers linked to firefighting.

2.2. Objectives of the Requirement The objective of the requirement is to measure the incidence of MN in urothelial cell samples and buccal epithelial cell samples collected from wildland firefighters engaged in active fire suppression. HC will first perform a small study that will utilize urine samples and mouth swab samples collected from 12 local individuals; these will serve as pilot samples to evaluate an in-house protocol for the preparation of samples derived from urine and buccal swabs. Subsequently, HC will collect 90 samples per fiscal year (FY) from wildland firefighters engaged in active fire suppression. Urothelial cells and buccal epithelial cells will be isolated from urine and buccal swabs, respectively, fixed, placed on glass microscope slides, and suitably stained for MN incidence determination. The MN incidence data will allow HC researchers Page 42 of 48 to address knowledge gaps pertaining to firefighter cancer risk; moreover, mitigation strategies to reduce risk.