Increased risk of breast cancer in women bearing a combination of large CAG and GGN repeats in the exon 1 of the androgen receptor gene.

The exon 1 of the human androgen receptor gene (AR) contains both CAG (polyglutamine) and GGN (polyglycine) repeat length polymorphisms. Large CAG repeats have been related to an increased risk of breast cancer (BC), whereas the influence of the GGN repeats is still unclear. Here, we have studied how the length of CAG and GGN repeats is associated with the risk of BC in a population from Tenerife (Canary Islands, Spain).