<prompt> BRCA-1 gene is located at chromosome location17p2l17q2113p2113q21  <response>: Roughly one third of women with hereditary breast cancer have mutations in BRCA1 at chromosomal locus 17q21.3 or BRCA2 located on chromosomal band 13q12-13. These genes encode large, complex proteins that do not exhibit close homology to each other or other proteins. Although the molecular basis for their strong association with breast cancer risk is still being elucidated, both BRCA1 and BRCA2 are believed to function in a common DNA repair pathway ref : Robbins Basic Pathology, 9E,page-709 