In the past three years, ground-breaking discoveries in the prostate cancer field have highlighted that alterations of ETS related genes (predominantly ERG), as a result of a fusion between male hormone receptor regulated gene promoters (predominantly TMPRSS2) and ETS transcription factors, represent one of the most common oncogenic defects in prostate cancer.

Researchers at the Center for Prostate Disease Research (CPDR) at the Uniformed Services University of the Health Sciences (USU) had originally shown frequent overexpression (60-70%) of the ETS related gene ERG in the epithelial cell transcriptome of prostate cancers. In their continued quest to understand the functional role and clinical utility of ERG alterations in prostate cancer, CPDR researchers have now defined new features of ERG function and expression which will further enhance the potential of ERG as promising biomarker and therapeutic target for prostate cancer.

Using cell culture and animal models and prostate cancer specimens from patients, the multi-disciplinary group co-led by Dr.Shiv Srivastava, Dr. David G. McLeod, Dr. Isabell A. Sesterhenn and Dr. Albert Dobi shows that inhibiting ERG expression in prostate tumor cells induces markers of prostate differentiation and inhibits tumor cell growth in mice.

This study also highlights the role of the C-MYC oncogene in mediating ERG functions in prostate cancer cells. Taken together, these novel findings strongly implicate causal roles of ERG in prostate cancer at least in part by affecting cellular differentiation. Moreover, this study underscores promising potential of ERG and C-MYC in developing new targeted therapy for a large percentage of prostate cancers with ERG overexpression (60-70%).

The second innovative CPDR study, co-led by Dr. Shiv Srivastava, Dr. David G. McLeod, Dr. Isabell A. Sesterhenn and Dr. Gyorgy Petrovics, defines full length transcripts and proteins encoded by common TMPRSS2-ERG fusions in prostate tumors. This study for the first time has led to the discovery of two major types of ERG products (type I: full length and type II: without ETS domain) in prostate tumors.

Surprisingly, they found an abundance of type II products in tumors cells. Although the functional role of the type II products is unclear, early data suggest that ratios of type I and type II products in prostate tumor cells may provide prognostic indicators for disease progression. New information from this study has promise to enhance future strategies for utilizing specific ERG products as biomarkers or as therapeutic targets.

Further studies are also warranted that would address the role of specific ERG products in overall ERG functions in prostate cancer. Towards these goals the CPDR team has been recently awarded a three year grant from the DoD-Prostate Cancer Research Program.

The Uniformed Services University is located on the grounds of Bethesda's National Naval Medical Center and across from the National Institutes of Health. It is the nation's federal school of medicine and graduate school of nursing. The university educates health care professionals dedicated to career service in the Department of Defense and the U.S. Public Health Service.

Students are active-duty uniformed officers in the Army, Navy, Air Force and Public Health Service who are being educated to deal with wartime casualties, natural disasters, emerging infectious diseases, and other public health emergencies. Of the university's more than 4,200 physician alumni, the vast majority serve on active duty and are supporting operations in Iraq, Afghanistan, and elsewhere, offering their leadership and expertise.

About Prostate Cancer

Prostate cancer is a disease in which cancer develops in the prostate, a gland in the male reproductive system. It occurs when cells of the prostate mutate and begin to multiply out of control. These cells may spread (metastasize) from the prostate to other parts of the body, especially the bones and lymph nodes.

Many factors, including genetics and diet, have been implicated in the development of prostate cancer. Prostate cancer develops most frequently in men over fifty. This cancer can occur only in men, as the prostate is exclusively of the male reproductive tract. It is the most common type of cancer in men in the United States, where it is responsible for more male deaths than any other cancer, except lung cancer.

Advanced prostate cancer can spread to other parts of the body and this may cause additional symptoms. The most common symptom being bone pain, often in vertebrae (bones of the spine), pelvis or ribs. Spread of cancer into other bones such as the femur is usually to the proximal part of the bone. Prostate cancer in the spine can also compress the spinal cord, causing leg weakness and urinary and fecal incontinence.