Very little is known about the cause of uterine fibroid tumors, although scientists have suggested several provocative theories. Unfortunately, none fully explains why fibroids develop, let alone why some remain harm-less and others become such renegades and sources of both physical and emotional pain. Recent studies have suggested that hormones, the environment, and genetics may be underlying causes, but no one knows for sure. Clinicians have long recognized that fibroid growth is intimately linked with the secretion of estrogen. When women reach menopause and ovarian hormone production declines, fibroids tend to shrink dramatically, and in many women, they even disappear.
But some scientists contend that the estrogen link may be more associated with the growth of fibroids as opposed to what makes them develop in the first place. While some experts have said the tumors tend to grow in women who produce higher than normal levels of estrogen, laboratory tests have shown that some women whose estrogen secretion is clearly within normal ranges also develop the growths.
Scientists are vigorously searching for clues about the origin, growth, and ultimate shrinkage of fibroid tumors. If enough clues are found, medical scientists believe they will be able to piece together a sketchy outline of the natural history of fibroid tumors. Already, at least one prominent clue has surfaced. It involves recent discoveries about certain proteins found in fibroid cells. These dis-coveries may ultimately help scientists unveil further information about how fibroids seed themselves in the uterus and then grow under the influence of estrogen.
Researchers in the reproductive endocrinology division of the National Institutes of Health have found that fibroids have very low levels of a key structural protein that helps hold normal tissue in place. The protein is called dermatopontin and it is a major chemical component your body makes to prevent cells from straying into aberrant patterns of growth. In a healthy uterus, adequate supplies of dermatopontin help maintain the integrity of the organ by keeping uterine cells where they are supposed to be. Fibroids and similar benign growths (such as keloids, which are a type of thick tissue that forms after an incision or wound) tend to have low levels of dermatopontin.
A lack of sufficient supplies of the protein may explain why a small portion of the uterus inexplicably develops a fibrous nodule that, over time, can grow until it reaches the size of a golf ball or even a cantaloupe and becomes what is known as a fibroid tumor. If you were to view fibroid tissue under the micro-scope, you would notice that its very low levels of dermatopontin cause the tumors to have very disorganized and unstructured strands of collagen. Aside from that feature and the very fact that fibroids tend to have low levels of dermatopontin, scientists have yet to discover other roles that the protein may have in the uterus, Studies of this important chemical component in uterine cells, however, are continuing. Meanwhile, scientists at the National Institute of Environmental Health Sciences have been researching whether chemical compounds in the environment, mostly pesticides, are capable of mimicking estrogen. If so, scientists are asking whether these chemicals are linked to the development of fibroids and other reproductive system disorders, such as endometriosis.
Estrogen-like compounds are common in the environment and some scientists have theorized that these chemicals compete with your body’s natural estrogen for sites on your cells known as estrogen receptors. It is theorized, but not yet proven, that once a fake estrogen molecule latches onto an estrogen receptor, it can not only block natural estrogen, but it may also unlock the cell and serve as the fuel that drives its growth. The result, the theory holds, may be abnormal growth, such as what your doctor detects in the case of fibroids and other female reproductive system disorders.
Doctors have also long known that women with first-degree relatives diagnosed with the growths are more likely to have fibroids themselves. Problematic fibroids are often seen among relatives, and this observation has had an influence on hysterectomies that have occurred over multiple generations in families. Many American women may feel the necessity to have hysterectomies based on their mothers’ or other relatives’ experiences. Scientists at the National Institutes of Health (NIH) estimate that, while vast numbers of women develop uterine fibroid tumors, about 75% of patients who are diagnosed with them never experience symptoms.