Androgen receptor CAG and GGN repeat length variation contributes more to the tumorigenesis of osteosarcoma.

The androgen receptor (AR) is involved in the differentiation and growth of many cancers. We hypothesized that two microsatellite polymorphic variants, AR (CAG)n and (GGN)n repeats, were also associated with the development of Papillary thyroid cancer (PTC) and Osteosarcoma. In current study, we conducted two case-control studies in a Chinese population to investigate the possible relationship between these two AR repeat polymorphisms and the risk of PTC and Osteosarcoma. The AR CAG repeat length was significantly associated with both risk of PTC and Osteosarcoma. Subjects with shorter AR CAG repeats had a higher risk of developing PTC (OR = 1.47, 95% CI: 1.17-1.85, P = 0.001) and Osteosarcoma (OR = 1.53, 95% CI: 1.19-1.97, P = 9.2 x 10-4). Specifically, shorter GGN repeats also contribute a significant increased risk of Osteosarcoma (OR = 1.35, 95% CI: 1.03-1.77, P = 0.030). Our results contribute to a better understanding of the complex hormone related mechanisms underlying PTC and Osteosarcoma.