MedWire News: Overexpression of cyclin E in ovarian cancer patients is linked to a high number of lifetime ovulatory cycles (LOCs), largely due to oral contraceptive use and pregnancy, US researchers have discovered.

Cyclin E overexpression is associated with poor cancer outcomes. Joellen Shildkraut and colleagues from Duke University Medical Center in Durham, North Carolina, therefore studied cyclin E expression in 538 cases of epithelial ovarian cancer and 629 controls.

Immunohistochemistry revealed that 40.5 percent of the ovarian cancer cases had cyclin E overexpression, the team notes.

Cyclin E overexpression in ovarian cancer was significantly more common in women who had a moderately high number of LOCs, at 265-390 cycles, and those who had a high number of LOCs, at over 390 cycles, than women with less than 265 LOCs, at odds ratios of 1.8 and 2.7, respectively. However, LOCs were not associated with ovarian cancer in women who did not have cyclin E overexpression.

Further analysis revealed that variations in LOC in cyclin E ovexpression patients was associated with months of oral contraceptive use and pregnancies per year, at odds ratios of 0.91 and 0.81, respectively.

The team concludes: "Specific ovarian cancer risk factors may lead to the development of ovarian cancers that are characterized by distinct molecular signatures."

Journal abstract