Uterine leiomyomas, also known as fibroids, are very common in women, with approximately 20-40% of women over the age of 30 years being affected. Leiomyomas are benign, mesenchymal tumors of the uterus, arising from overgrowth of uterine smooth muscles and connective tissues. Usual symptoms of the disease include heavy menstrual flow resulting from erosion of submucosal fibroids into the endometrial cavity, bleeding between periods, pain, pelvic pressure, urinary frequency, incontinence, and uretral obstruction. Leiomyomas may also interfere with implantation, causing infertility. Complications of the disease include malignant degeneration of the leiomyoma into a sarcoma. During pregnancy, additional complications, such as spontaneous abortions, growth retardation, preterm labor, postpartum hemorrhage and/or hydronephrosis may be seen.
Leiomyomas can be identified by imaging techniques, such as transabdominal or transvaginal ultrasonography as well as MRI and CT scans. Treatment usually involves a surgical option. In fact, hysterectomy is the only permanent cure. Myomectomy, which involves removal of only the fibroid, without removing the uterus, is recommended for women who may want to have children. However, the recovery time for this procedure is very long, and there is an increased chance for infection. Embolization is another treatment strategy in which blood flow to the fibroids are blocked, causing them to degenerate. Gonadotropin releasing hormone (GnRH) analogues may be administered prior to surgery to reduce the size of the fibroids.
Cytogenetic analyses of leiomyomatas have shown that at least 40% of these tumors have recurrent chromosome abnormalities. The most common of these are aberrations in chromosomes 6p and 12q. The gene HMGA2 (High Mobility Group at-Hook 2), present on chromosome 12q has been frequently found to be translocated in this disease. A typical reciprocal translocation involving HMGA2 and its preferred translocational partner in UL, RAD51B, is represented as t(12;14)(q14-15;q23-24).
Uterine leiomyomas have been also observed with other fusion partners of the HMGIC gene, namely ALDH2, COX6C, and HEI10. Uterine leiomyomata also occur in association with skin leiomyomata and renal cell cancer on the basis of mutations in the gene encoding fumarate hydratase (FH). Other chromosomal aberrations in UL include trisomy 12, rearrangements involving chromosome 10q, and deletions of 3q.