September 23, 2011

Ovarian Cancer Breakthrough

(Ivanhoe Newswire) -- Ovarian tumors can be deadly - especially if gone undetected like so many are. A new study, published in the September 20 issue of PLoS Biology, may shed light on how these deadly tumors develop and spread.

Stanford researchers, including Patrick O. Brown, senior author of the study and Howard Hughes Medical Institute investigator, were specifically looking for evidence that an ovarian tumor had rearranged its DNA so that two distinct genes were now fused together.

Identifying a gene fusion in ovarian cancer may provide a new opportunity to catch ovarian cancers early in their development, and possibly find new treatments.

The study discovered that a gene, ESRRA, which is closely related to the estrogen receptor, is broken and fused to an adjacent gene called C11orf20. The fusion occurred in about 15 percent of serous ovarian cancer cases tested.

A particularly lethal cancer, serous ovarian cancer is the most common form of ovarian cancer. It is usually only detected at a late stage in its progression, after the cancer has spread to other tissues.

The fact that ovarian tumors in many patients share the same genetic change suggests that it may be important for the way they behave. The discovery might provide a marker for detection of some cancers at a curable stage.

"More study will reveal if this gene fusion contributes to the tumor's aggressive growth and spread," Brown was quoted as saying.

The integration of a relatively new technology - "deep sequencing" - with tools from genetics, computer science, and statistics were used during the research leading to the discovery. The gene fusion was found by searching through a vast pile of data from "deep sequencing" of genes active in ovarian tumors.

"Many groups have hoped to find recurrent gene fusions in different cancers using deep sequencing, but it has proved more difficult than expected," researcher Julia Salzman was quoted as saying. "We spent months designing computer and statistical algorithms to sort out signal from noise," Salzman added.

Finding that ESRRA and C11orf20 are fused together, may give insight into what happens as ovarian cancers develop. It also serves as proof that deep sequencing can uncover recurrent gene fusions.

The findings were not just a fluke. Collaborators in the Canary network at the Fred Hutchinson Cancer Research Center in Seattle, and the British Columbia Cancer Research Agency in Victoria, confirmed the presence of the gene fusion in multiple ovarian cancers.

Future studies are in process that will test whether additional important genes can be found in ovarian tumors.

"We are testing our algorithms on publicly available data and hoping it might lead to more discoveries," Brown was quoted as saying.

SOURCE: PLoS Biology, published online September 20, 2011