Brazilian biorepository to support genome-wide association studies of colorectal, breast, and cervical cancer

Genome-wide association studies (GWAS) have identified numerous genetic variants associated with cancer susceptibility. However, over 90% of participants are of European ancestry, limiting the applicability to highly admixed groups such as Brazilians. To address this gap, we established a large-scale Brazilian biorepository to support cancer GWAS, replication studies, and polygenic risk score (PRS) evaluation for colorectal, breast, and cervical cancers. 4,062 participants have been enrolled, including cancer cases and cancer-free controls, yielding 39,700 blood-derived biospecimens. Genotyping was performed in 2,844 participants using the Axiom 850K PMDA array. All Brazilian states were represented, with the majority of participants from the Southeast region. Genetic ancestry inference confirmed Brazil's highly admixed genetic background, with predominant European, followed by African, Native American, and Asian contributions. This biorepository provides a scalable resource to enable replication of genetic associations, assess the transferability of polygenic risk scores, and advance precision medicine in underrepresented populations.