Related Experiment Video
Updated: Apr 4, 2026

Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 16, 2010
Androgen receptor (CAG)n polymorphisms and breast cancer risk in a Han Chinese population
1Key Laboratory of Fertility Preservation and Maintenance, Ningxia Medical University, Ministry of Education, Yinchuan, China.
Abstract:
The androgen receptor (AR) is involved in the differentiation and growth of breast cancer. Genetic markers in the AR gene have a plausible role in modulating the risk of breast cancer. In this study, we studied the association of breast cancer and the trinucleotide repeat polymorphism (CAG)n in exon 1 of the AR gene in 202 patients with breast cancer and 183 healthy controls from our hospital (Yinchuan, China). Repeat lengths were determined by fluorescent DNA fragment analysis using the ABI GeneScan software and DNA sequencing. We detected 17 short tandem repeat alleles in exon 1 in the Han population of Ningxia Province, China. The CAG repeat number ranged from 14 to 31 and the frequency ranged from 0.339 to 24.460%. Generally, (CAG)n repeat lengths <22 were classified as short (S), and those >22 were classified as long (L). No association was found between breast cancer and the S/L (CAG) variants. However, the frequency of the (CAG)25 repeats in the breast cancer group was significantly higher than that in the control group (P = 0.033, odds ratio = 1.790, 95% confidence interval = 1.044-3.069). These findings indicate a role for AR gene (CAG)n variations in breast cancer and might be informative for future genetic or biological studies on breast cancer, although these findings need replication in other populations.
Related Concept Videos
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Single Nucleotide Polymorphisms-SNPs
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Abnormal Proliferation
Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...

