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.
