CATSPERZ and ovarian serous adenocarcinoma: Although it remains possible that the ESRRA-C11orf20 fusion is an incidental consequence of another, functionally important, genetic event or that it is merely a “passenger,” the apparent frequency with which this rearrangement occurs in serous ovarian cancer and the lack of evidence that it accompanies large-scale structural variation (such as gene amplification) are more suggestive of a direct role.