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June 26, 2013 By:
Breakthrough in Testicular Cancer Research?
Testacular cancer, the most common cancer for young males, is also one of the most inheritable cancers, according to research and reports on the disease.
To unlock how this cancer runs in families, a new study published online in Nature Genetics found four genetic variances in patients’ testicular germ cells, or the cells that produce sperm.
In the first meta-analysis for this disease, researchers at the University of Pennsylvania and National Cancer Institute pooled together their data on testicular cancer patients to come up with the results. Then researchers for five other independent studies replicated their findings.
All together, researchers analyzed the genomes of 3,211 affected males against 7,591 controls.
Dr. Katherine Nathanson, the study’s corresponding author and associate professor in the division of translational medicine and human genetics at the University of Pennsylvania, said during a recent telephone interview, “The important take home message about this disease — as opposed to some other diseases — is that a lot of the variance that we find are in regions in which” sperm is eventually developed.
Nathanson added that the link between testicular cancer and infertility has already been established. “What we’re finding is the genes may explain that link.”
Ashkenazi Jews in general — though not solely — seem susceptible to this disease, said the Penn researcher.
Furthermore, its incidence has more than doubled for white men in the United States over the past 30 years.
To explain this increase, Nathanson said some in the field have hypothesized that endocrine disruptors or chemicals like plastics in the environment are causing the increase. However, Nathanson stressed, “We don’t know if that’s really the case; it’s just some hypothesis, but the idea is that if we best understand what the genetics are, then we can help tease out what are the other influences.”
With the study’s four variances reported, a total of 10 variances are now conclusively associated with testicular cancer susceptibility. Nathanson added that since publication, another study has reported seven more variances, bringing the total to 17.
She said it’s still fewer than variances associated with breast and prostate cancers.
Rachael Brandt, a genetic counselor in the cancer risk assessment and genetics program at Main Line Health, is pleased that genetic researchers are now focusing on testicular cancer.
Brandt explained that comparable studies on cell variances associated with breast cancer led researchers to focus on specific locations in the chromosomes and identify the BRCA1 and BRCA2 genes. These discoveries, in turn, made it possible to develop more early detection and prevention measures for patients with genetically determined cancer risks.
Brandt said she believes advances in technology explain the increase in genetic studies of testicular cancer. She said different genes now can be tested easily, quickly and concurrently, while still being cost effective.
With limited resources, genetic testing used to be reserved for the more common cancers, like breast cancer, even if breast cancer has an estimated heritability rate of 10 percent while testicular cancer has one of 25 percent.
Mike Craycraft, survivor and founder of the Testicular Cancer Society in Cincinnati, said an estimated 230,000 women per year are diagnosed with breast cancer, compared to 8,500 men diagnosed with testicular cancer. He added, “But it’s also a cancer that really nobody should be dying from.”
While preventative measures remain unknown, Craycraft’s website says the survival rate for this cancer is 95 percent. Treatments include an orchiectomy, a surgical procedure that removes one or both testicles, and radiation or chemotherapy.
The Nature Genetics study reports that the peak incidence for this disease is between the ages of 25 and 34.
Except for when Lance Armstrong was diagnosed in 1996, guys don’t talk much about testicular cancer either, according to Craycraft. To explain some of the reticence, Craycraft said that males tend not to go to a doctor “unless something’s really broken.”
He added, “Luckily we do have a lot of women in our lives that help get us to the doctor and encourage us. You’d be amazed at how many guys are basically dragged in by their mom or their wife.”
To keep the conversation going, learn more about the cancer’s symptoms and discover how to navigate the healthcare system when diagnosed, go to: www.testicularcancersociety.org.