Adapted from the NCI Cancer Bulletin.
Researchers at Dana-Farber Cancer Institute in Boston, Mass., have found that the source of disease in many cases of the most aggressive form of ovarian cancer, serous carcinoma, may not be the ovary at all, but rather the fimbria of the fallopian tube. Dr. Keren Levanon reported these findings at the American Association for Cancer Research annual meeting on April 14, 2008.
"Until now, there was no understanding of the basic pathogenesis or carcinogenesis of [ovarian] serous carcinoma," said Dr. Levanon at the meeting. Noting that the majority of ovarian cancers are diagnosed at an advanced stage, she continued: "We didn't really know what the early cancer lesion or precursor lesion looks like, so we couldn't analyze what went wrong."
Her team, which included collaborators at Brigham and Women's Hospital, searched for these early lesions by identifying cells with a "p53 signature" - mutations in the p53 gene and buildup of p53 protein in cells - in the tissues of women who, due to a high risk for developing ovarian and other cancers, volunteered to have their ovaries and fallopian tubes removed.
The team found a p53 signature most often in the secretory cells lining the finger-like appendages, called fimbria, at the ends of fallopian tubes. Dr. Levanon's team then developed an ex vivo model that they are using to continue studying these cells and the molecular events that lead to cancer. They hope this research will lead to targeted therapies and biomarkers for early detection.
Though they were surprised by their findings, explained Dr. Levanon, they were not surprised that ovarian cancer could begin in the fallopian tubes. "When we look at patients who are diagnosed with later-stage ovarian cancer," she said, "we find that they have these lesions in their fallopian tubes in close to 100 percent of cases." She also noted that patients who have prophylactic surgery to remove their ovaries sometimes develop tumors in other parts of their abdomen, which could result from shed cancer cells when the fallopian tubes are left intact.