ANN ARBOR, Mich.--Research from the University of Michigan Women's Health Program suggests that gene therapy may someday control a condition responsible for nearly half the 550,000 hysterectomies performed in the United States each year.
Leiomyoma tumors---commonly known as fibroids---are benign growths that develop in the uterus and often cause pelvic pain, abnormal uterine bleeding, excessive urinary pressure, decreased fertility, and increased chance of miscarriage. Treatment typically involves a hysterectomy that excises the tumors along with the patient's uterus.
The U-M research, however, offers hope of a non-surgical alternative that would leave a patient's uterus, and fertility, intact. U-M physicians, administering DNA tailored to inhibit tumor growth, have effectively killed human leiomyoma cells in laboratory tests and suppressed leiomyoma tumors in lab rats.
The significance of this development is enormous, because fibroids are the most common tumor in humans and hysterectomy is the most common surgical procedure performed in this country. It is estimated that:
- Thirty percent of women develop leiomyomas.
- Ten percent to 15 percent of all women between the ages 25 and 64 require surgery for leiomyomas.
- One in three American women undergo a hysterectomy by age 65, approximately half of which are performed to alleviate medical problems caused by leiomyoma tumors.
"Leiomoyomas are an incredibly common problem," said Gregory M. Christman, M.D., an assistant professor and research scientist in the U-M Department of Obstetrics and Gynecology and lead investigator in the leiomyoma study. "Our treatment had a pronounced effect on them, suggesting it may ultimately be feasible to treat uterine leiomyomas with gene therapy."
The method of gene therapy Christman uses has been shown to inhibit the spread of malignant cancer cells, but malignancies grow too fast and DNA delivery systems currently are too imperfect to make gene therapy more than a subordinate cancer treatment, he says. On the other hand, uterine leiomyoma cells are benign and slow-growing and their symptoms can be relieved by reducing the tumors. Unlike malignant cells, eliminating them is not necessary. Gene therapy that inhibits leiomyomas, therefore, may be sufficient treatment.
A paper in the current issue of the journal Obstetrics & Gynecology details the results Christman and his colleagues produced in laboratory tests on human and rat leiomyoma cells. In addition, Christman reported the results of subsequent tests on lab animals during the annual meeting of the American Society of Gene Therapy in Seattle on Friday (May 29).
The U-M researchers' next step is to investigate the effectiveness of various systems for delivering the genes in the body. Christman estimates it will be another two to three years before they are ready to begin human trials.