Estrogen helps drive distinct, aggressive form of prost...(st-line treatment against the disease. A...)

"So, we wanted to learn more -- what is the genetic and molecular 'fingerprint' of this aggressive subset of prostate tumor"" Dr. Rubin says.

Answering that question required the analysis of 455 prostate cancer samples from trials in Sweden and the United States that were conducted as far back as the mid-1970s.

"These samples were placed in fixative and not frozen, so we needed new methods of retrieving the genetic information," Dr. Rubin says. To do so, his team led by co-lead authors Dr. Sunita Setlur and Dr. Kirsten Mertz developed an innovative technology for effectively "reading" the gene transcription profiles hidden in the samples.

"That led us to perform the largest gene-expression microarray analysis yet conducted in prostate cancer research, amassing information on more than 6,000 genes," Dr. Rubin says. "This allowed us to obtain a robust, 87-gene expression 'signature' that distinguishes fusion-positive TMPRSS2-ERG cancers from other prostate malignancies."

A close analysis of the signature yielded a surprise: that estrogen-dependent molecular pathways appear to play a crucial role in regulating (and encouraging) this aggressive subset of prostate cancer.

While estrogen is typically thought of as a "female" hormone, men produce it as well.

"Now, we show for the first time that this natural estrogen can stimulate the production of the cancer-linked TMPRSS2-ERG transcript, via the estrogen receptor (ER)-alpha and ER-beta. These receptors are found on the surface of some prostate cancer cells," Dr. Rubin explains.

The finding could have implications for prostate cancer research, including drug development. According to Dr. Rubin, "We now believe that agents that dampen estrogen activity (ER-beta antagonists) could inhibit fusion-posit
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