A woman’s chance of surviving ovarian cancer may be linked to levels of two proteins, US researchers reported in Thursday’s issue of the New England Journal of Medicine. More exactly, women suffering from ovarian cancer who have low levels of the two proteins die much sooner than women with high levels of the proteins.
The proteins involved in the study are known as Dicer and Drosha. They seem to play a key role in two types of RNA interference, which is the mechanism by which genes are turned on and off.
The study is the largest to link RNA interference with cancer survival rates, and the researchers also found that high Dicer levels are linked to survival in breast and lung cancer. Drosha has less of an association in these cancers.
For the new study, Anil K Sood, M.D., of the University of Texas M.D. Anderson Cancer Center, in Houston, and colleagues analyzed tissue from 111 women with advanced epithelial ovarian cancer, looking for the two proteins. They found 60 percent of the cancers had low levels of Dicer, 51 percent had low levels of Drosha, and 39 percent had low levels of each.
Moreover, women who had ovarian tumors with high levels of the two proteins survived for a median of 11 years or more, while those having lower levels survived for a median of about 2.6 years, the study found.
The study may have “many, many implications for the diagnostics and prognostic of cancer,” Dr. Sood said. Most ovarian cancers are diagnosed in the advanced stages of the disease, and that’s part of the reason why they have such poor overall survival.
The findings help scientists better understand the biological details of the RNA interference process. By understanding this process, they can better tailor drugs to impair the ability of tumor cells to multiply. The researchers anticipate beginning clinical trials of those drugs within a few years.
Ovarian cancer, named “the silent killer” because it has no specific symptoms in early stages, is the fifth leading cause of death from cancer in women and the leading cause of death from gynaecological cancer.
According to the American Cancer Society, more than 21,000 women will be diagnosed with ovarian cancer this year. The disease kills more than 15,000 women each year. The bad news is that only 20 percent of ovarian cancers are caught in their earliest, potentially curable stages. Older women and those who have a first-degree relative with the disease are at high risk of developing ovarian cancer.
Symptoms that may suggest a woman is at risk of ovarian cancer include abdominal pain, a feeling of fullness after a small meal, having trouble eating, and abdominal bloating.
