English: The BRCA genes are tumor suppressor genes pictured here on their respective chromosomes. BRCA 1 has the cytogenetic location 17q21 or the q arm of Chromosome 17 at position 21. BRCA 2 has the cytogenetic location 13q12.3 or the q arm of Chromosome 13 at position 12.3. Both genes produce proteins that help repair damaged DNA, keeping the genetic material of the cell stable. A damaged BRCA gene in either location can lead to increased risk of cancer, particularly breast or ovarian in women.