Insulin-Like Growth Factor I Polymorphisms in Breast Cancer

摘要

Insulin-like growth factor I (IGF-I) is an important regulator of growth and differentiation, is known to inhibit apoptosis, is a potent mitogen for human breast cancer cells, and may influence proliferation of the cells of early breast cancer. A number of epidemiologic studies have evaluated the association between plasma IGF-I and breast cancer and have found that pre- menopausal women with higher levels of IGF-I show an elevated risk. Genetic analysis has identified a highly polymorphic region of the IGF-I gene consisting of cytosine-adenine (CAn) dinucleotide repeats 1 kb upstream from the transcription start site. The relation between circulating IGF-I levels and the polymorphisms has been shown to vary according to the number of these CA repeats. This project is assessing the role of IGF-I polymorphisms in breast cancer, evaluating the relationship between the number of CA repeats in the IGF- I gene and plasma IGF-I levels, and determining if menopausal status confers differential risk of breast cancer in women with particular genotypes. Progress on this project includes completion of laboratory training for techniques used in genotyping DNA samples. Aliquoting of samples has been completed and assay for PCR analysis has been developed and is currently being used to determine genotypes.