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Endometriosis: Developments in Gene Research
By Leigh Ann Woodruff, February 9, 2012
Endometriosis is a condition in which uterine tissue grows in other parts of the body, such as the abdominal cavity, ovaries, vagina, and cervix. The condition affects millions of women — 5 percent to 15 percent of women of reproductive age — causing chronic pain and infertility.
Endometriosis is often hereditary, and now researchers at the Yale School of Medicine have found an inherited mutation located in part of the KRAS gene, which leads to abnormal endometrial growth and endometrial risk. The KRAS gene makes the KRAS protein, which is involved in cell signaling pathways, cell growth and cell death. It is believed that this gene may cause cancer when it is mutated.
"This tells us that a single gene mutation leads to endometriosis in some women," says Hugh S. Taylor, M.D., professor and chief of the Division of Reproductive Endocrinology and Infertility in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale. "Not all endometriosis is caused by this variation, but in those who have this type of endometriosis, we can track it and its inheritance. We can start to personalize treatment and perhaps target therapies that work towards this new pathway.”
The Gene Research
Even though endometriosis has been studied for many years, its causes and how it develops had remained unclear. In the past, researchers had shown that activating the KRAS gene in mice caused them to develop endometriosis. For this recent study, published in EMBO Molecular Medicine. the researchers evaluated 132 women with endometriosis for a newly identified mutation in the region of the KRAS gene responsible for regulation. This mutation had been previously linked to an increased risk of lung and ovarian cancer.
"We found that 31 percent of the women with endometriosis in the study carried this mutation, compared to only 5.8 percent of the general population," Dr. Taylor says. "The presence of this mutation was also linked to higher KRAS protein levels and associated with an increased capacity for these cells to spread. It also may explain the higher risk of ovarian cancer in women who have had endometriosis."
Discovering the mutation could allow researchers to target new therapies for endometriosis, as well as create new screening methods to determine who is at risk for developing the condition.
"In the future we may be able to screen in a way similar to what we do now for genetic risk of breast cancer," Dr. Taylor explains. "Not all breast cancers are due to a BRCA gene mutation, but if it is, we know a lot about how it behaves and can screen other family members."
Diagnosing and Treating Endometriosis Today
Symptoms of endometriosis include severe pain during menstruation and intercourse; however, the only way to accurately diagnose the condition is via diagnostic laparoscopy, a minor surgical procedure in which a tiny scope with a camera is placed through an incision in the abdomen. This allows the surgeon to clearly view the pelvic and abdominal organs and check for endometrial growths.
There is currently no cure for endometriosis, and treatment depends on the patient's goal — whether it is to reduce pain, stop progression of the disease or preserve/restore fertility.
"The initial treatment of endometriosis should always be surgical," says Amos E. Madanes, M.D., a fertility doctor and medical director of Midwest Fertility Center in Illinois. "The main reason is that laparoscopy or other exploratory surgery is currently the only way to actually establish the diagnosis of endometriosis."
Dr. Madanes explains that most experienced laparoscopic surgeons can use the initial surgical intervention to remove all the visible endometriotic lesions. "This is usually sufficient to help that patient conceive, especially when endometriosis plays a significant role in their infertility," he says. "We have many patients that conceive with no other treatment after surgically removing endometriotic lesions."
GnRHa therapy may be used to reduce the pain of endometriosis. This is a non-surgical treatment using Gonadotropin-Releasing Hormone Agonists to lower estrogen levels in the body, which decreases the size of endometrial growths to provide relief of symptoms.
"Treatments depend on the stage of the disease and whether the patient is attempting to conceive or just needs long term symptomatic relief and prevention of destruction of pelvic organs," Dr. Madanes explains. "Long term maintenance is usually hormonal, while occasional surgical interventions are indicated as per the symptoms or desire to conceive.
"There is a lot of exciting new research in the area of endometriosis," he continues, "and we are all looking forward for major developments in the diagnosis and treatment of this very common disease."