Dr. G. Shyamala

Life Sciences Division, Lawrence Berkeley National Laboratory

Mailing Address: One Cyclotron Road, Mailstop: 74-157, Berkeley, CA 94720

Email Address: shyamala_harris@lbl.gov

Dr. Shyamala's laboratory investigates the role of sex steroids in induction of mammary cancers. While most of the studies have been concerned with the carcinogenic actions of estrogens, this laboratory focuses on investigating the role of the progesterone receptor (PR) in normal and abnormal mammary development. A principal rationale for this is that, in adults, it is progesterone acting through PR that leads to proliferation and subsequent differentiation. It also appears that, in post menopausal women on hormone replacement therapy (HRT), the hormone responsible for promoting carcinogenesis is progesterone. The PR exists in two molecular forms, A and B, whose action can vary in action and cell promoter context; both forms can inhibit the activity of the estrogen receptor (ER). An imbalance between ERs and PRs (A and B) may result in altered ER and PR dependent gene expression and lead to alteration in cell replication (probably mediated through specific growth factors), thereby triggering mammary cancer. To further explore this hypothesis, Dr. Shyamala's laboratory utilizes transgenic mice (overexpression of these receptors ) at various ages and development. Such studies can provide insight for arresting the generation of preneoplasias and other progressions to carcinoma.