Cause of rare cancer discovered at UConn

By: Frances Morales

Posted: 11/12/03

Researchers at UConn Health Center have discovered the cause of a rare form of cancer developed in the parathyroid gland.
In an article published in the New England Journal of Medicine, researchers performed several studies observing 15 patients who suffered from problems with their parathyroid glands, in hopes of finding a link between the gene HRPT2.
Further investigation is necessary for researchers to conclude if the cancer is associated with a genetic defect, thus inheritable.
For the past decade, genetical researchers at the Center of Molecular Medicine had no success within any genetical candidates, until now. They had not been able to find the genetic candidate to match up with the mutation Dr. Andrew Arnold, the director of the center, said.
"Up to this point nothing was known about the cause for this rare form of cancer," Arnold said. "This turned out to be a jackpot."
The recent discovery may assist researchers in identifying the cancer if the families of parathyroid cancer patients may be in danger of inheriting the cancer.
"The important part of this discovery is that we found that certain patients even those of no inheritance, had indeed inherited and could likely pass onto their children," Arnold said.
Many researchers had known that the "root cause of cancer are mutations of genes and when there are mutations in the cells it thus develops into a tumor," Arnold said.
Genetical researchers found that people with parathyroid carcinomas, genes in which are highly activated or sporadic, frequently have HRPT2 mutations.
"[With] the DNA sequence found in large majority, we can demonstrate mutations within the gene, making those mutations the cause of the tumor," Arnold said.
The study found that 10 of the 15 patients were found to have with HRPT2 mutations.
Patients involved in the study were those who had no known family history of hyperparathyroidism (sporadic activity of cells in the parathyroid gland).
Parathyroid problems occur when the glands are highly activate, thus producing too much parathyroid hormone (PTH).
"Too much production of PTH in the blood calcium can reach out of the bones causing severe bone diseases such as osteoporosis and kidney stones," Arnold said.
Although parathyroid disease is common, cancer of the parathyroid gland is very rare. In fact, one of every 1,000 patients who have parathyroid disease or tumors develops cancer in the gland, according to EndocrineWeb.com.
"Tumors develop when there is an overproduction of the parathyroid hormone (PTH)," Arnold said.
Arnold said there are two forms of tumors. One benign tumor called adenoma can be easily removed surgically. The parathyroid cancer tumor is the tumor which can spread to other areas.
"Once it [spreads throughout the body] it cannot be cured," Arnold said.
According to EndocrineWeb.com, the parathyroid gland becomes cancerous when the overgrowth is composed of noxious cells. These malignant cells grow out of control developing massive tumors which later could grow cancerous.
The Web site also said the parathyroid glands are small glands of the endocrine system which are located behind the thyroid. The sole purpose of the parathyroid glands is to regulate the calcium levels in our bodies with a very narrow range so that the nervous and muscular systems can function properly.
"The parathyroid gland is a system that is designed to control the blood calcium," Arnold said.
For years it has been hard for pathologist to detect the rare form of cancer under the microscope. Doctors make diagnoses through discovering very high parathyroid hormones and serum calcium levels.
According to Arnold, the common way to detect parathyroid cancer is through routine testing of high blood calcium.
"Many times existence will come to life from screenings," Arnold said. "Another way of detecting is if one has noticeable symptoms and problem of the digestive and/or neurological system, pain in the bones, or kidney stones."
Like most cancers, parathyroid cancer can be cured and treated if detected early.
Such forms of treatments for all patients who suffer from the rare cancer are through surgery, removing the cancerous tissue or through radiation therapy, using high doses of X-rays to kill the cancerous cells, according to Endocrineweb.com.
A way of preventing from this happening is through genetic testing of germ line of mutations, according to Arnold.
Arnold said that once it is discovered that the patient has the rare cancer, then he or she can begin looking at their kids by regularly testing their blood calcium. Once the cancer has been detected, performing surgical removal will successfully prevent the cancer from becoming severe.
"This will help identify family members at risk," Arnold said.
Researchers hope that those particular kids who have relatives with parathyroid cancer will participate in standard blood testing.