[Frontiers in Bioscience 10, 2346-2372, September 1, 2005]

GENES RELATED TO ESTROGEN ACTION IN REPRODUCTION AND BREAST CANCER

Aninda Basu and Brian G. Rowan

Department of Biochemistry and Cancer Biology, Medical College of Ohio, 3035 Arlington Ave, Toledo, OH 43614

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Genes involved in estrogen action in breast cancer
3.1.Estrogen Receptor
3.1.1. ER expression in normal breast tissue and breast cancer
3.1.2. ER-alpha-positive and ER-alpha-negative tumors
3.1.3. Targeted disruption of ER in mice
3.2. Cyclin D1
3.3. C-Myc
3.3.1. Role of c-Myc in cell proliferation
3.3.2. Role of c-Myc in cell transformation
3.3.3. The c-Myc gene in human breast cancer
3.4. pS2
3.5. Progesterone Receptor
3.6. Cathepsin D
3.7. C-fos
3.8. BRCA1
3.9. EGF, EGFR and Transforming growth factor-alpha (TGF-alpha)
3.10. Bcl-2
4. Perspective
5. References

1. ABSTRACT

Estrogen is an important steroid hormone with diverse functions in different parts of the human body. The developmental and physiological role of estrogen is mediated by estrogen receptor alpha (ER-alpha) and newly identified ER-beta. Regulation of expression of various important cellular oncogenes and tumor suppressor genes is a key component of estrogen and ER action. The expression of these genes is crucial in various processes such as cell cycle progression, mammary gland development, growth factor pathways and apoptosis. A very precise and accurate control of these genes is required for normal growth and functioning of cells. Aberrant expression of these genes through elevated expression, gene amplification or mutation may lead to induction and/or progression of different cancers including estrogen-dependent breast cancers. This review briefly describes the role of different genes that are regulated by estrogen in female reproductive tissues and breast cancer.