THURSDAY, Oct. 27 (HealthDay News) -- Researchers have stumbled across an unexpected genetic phenomenon in prostate cancer -- a discovery that could change conventional thinking on breast, colon and lung malignancies as well.

Looking through a library of genes involved in a variety of cancers, a team led by researchers at the University of Michigan found that prostate cancer samples revealed something hitherto only seen in blood-related cancers -- a recombination of genes that turned cells malignant.

"It was a serendipitous discovery, something very surprising to us," said Dr. Arul Chinnaiyan, a pathology professor at the university and lead author of a report in the Oct. 28 issue of Science.

"We were looking for genes that we thought might be oncogenes [cancer-causing]. We found these two genes, which inspired us to look further. Then we looked at the expression transcript and found a new gene. And then we found another gene," Chinnaiyan added.

These new genes were created by combinations of other genes: A prostate gene designated TMPRSS2 fused with two other genes, ETV1 and ERG. The combination caused the ETV1 and ERG genes to be unusually active, presumably driving the growth of the cancer cells, the experts said.

Rearrangements of those genes have been implicated in the genesis of Ewing's sarcoma, a relatively rare bone cancer, and similar combinations caused by gene rearrangements have been found in leukemias and lymphomas.

What makes this latest discovery in prostate cancer so remarkable is that this is an epithelial cancer, a malignancy of the tissue that lines organs, Chinnaiyan said. Breast cancer, colon cancer and lung cancer also are forms of epithelial cancer.

"It is likely that prostate cancer is not special in this regard," he said. "Breast cancer and colon cancer might have similar rearrangements that haven't been found as yet."

According to Chinnaiyan, the finding may trigger "a major paradigm shift in cancer," opening up a new frontier in research into the disease.

"I agree," said Sudhir Srivastava, chief of the Cancer Biomarkers Research Group at the U.S. National Cancer Institute, which funded the research. Other scientists will soon be looking for similar gene arrangements in other cancers, Srivastava said, using the same widely available libraries of cancer genes that led to the prostate cell discovery.

"With the power of bioinformatics, we now have banks of cancer genes," Srivastava said. "We can analyze them and look for candidates in other cancers."

But this is only a first step, he added. "This is a first discovery. The next step is to replicate it. This is a work in progress that will have to be validated by work with larger sample sizes," he said.

The finding will have no immediate impact on medical practice, Chinnaiyan said, but it does have longer-term implications "at the level of therapy as well as diagnosis. One can speculate that in prostate cancer, we could develop inhibitors of the genes to create a more rational treatment of the cancer."

A similar discovery of gene rearrangement in chronic myeloid leukemia (CML) led to development of Gleevec, a drug that's proven extremely successful in treating that cancer, he noted.

More information

For more on cancer genetics, head to the National Cancer Institute.