SNPwatch: Two Gene Variations Linked to Thyroid Cancer

SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.

Each year in the United States, about five out of every 100,000 men and 14 out of every 100,000 women develop thyroid cancer.  The number of diagnosed cases has been increasing over the past few decades, but the number of deaths due to the disease – about 1,500 per year – has remained the same.  Experts have suggested that this means the number of people affected by the disease is not actually changing, just the number found by physicians.

Studies have shown that genetics plays a larger role in thyroid cancer compared to other malignancies, but not much is known about the specific genes or variations that might be involved.  Now, a study being published online today by the journal Nature Genetics has identified two variations that together can increase the risk of thyroid cancer more than five-fold.

In a combined analysis that compared more than 960 subjects with thyroid cancer from Iceland, Spain and the United States to more than 38,000 controls, Julius Gudmundsson and colleagues found that each A at SNP rs965513 increased the odds of the disease by 1.75 times. Each T* at rs944289 increased the odds of thyroid cancer by 1.37 times.

According to the authors, about 3.7% of the population with European ancestry has the riskier version at both copies of both SNPs.  These people are estimated to have 5.7 times greater odds of developing thyroid cancer compared to people who carry no risky versions of either SNP.

The riskier versions of both SNPs were also associated with decreased blood levels of thyroid stimulating hormone, a key regulator of thyroid function that is secreted by the pituitary gland.  The A version of rs965513 was also associated with changes in the blood levels, of T3 and T4, two hormones made by the thyroid itself.

“Compared to the common susceptibility variants recently discovered for complex diseases, the relative risks associated with the variants reported here are quite high….Furthermore, we have demonstrated that these variants influence crucial players in the thyroid hormonal pathway.  These variants are therefore likely to be among the most important determinants of genetic susceptibility to thyroid cancer,” the authors conclude.

* The original post contained an error, identifying the C version of rs944289 as the version that is associated with increased odds of thyroid cancer.  In fact, it is the T version of this SNP that increases odds by 1.37 times.  We apologize for this mistake, and thank the Spittoon reader who brought it to our attention.


  • shutrbug

    Will 23andme perform this analysis for their customers as part of the standard offering?

  • http://www.23andme.com MattC

    Generally we wait to see if new research like this is replicated by other studies before including it. If more papers come out that confirm this result, we will include it.

  • http://www.23andme.com ErinC

    For now, 23andMe customers can check their data for the SNPs mentioned in this blog post using the Browse Raw Data feature. Simply type in the SNPs (rs965513 and rs944289) or use the links in the post.

  • Les Lambert

    One of my identical twin daughters has Hurthle cell thyroid cancer, which has been resistant to treatment for some time now. Are there genetic predispositions to this? I’m worried about the other twin, who so far has not shown this problem…

    Thanks

  • http://www.23andme.com ErinC

    I’m sorry to hear about your daughter’s condition.

    The study discussed in this post does not specifically mention Hurthle cell thyroid cancer. Instead it addresses thyroid cancer more generally. So it is possible that the common DNA variations associated with increased risk for thyroid cancer the researchers found would apply to Hurthle cell cancer, but I can’t say for sure.

    It seems that not much is known about the genetics of Hurthle cell thyroid cancer. Some work to understand that mutations that happen in tumors as they develop (as opposed to inherited mutations) has been done. For more information, check out the Pathophysiology section of this emedicine article: http://emedicine.medscape.com/article/279462-overview

    Other sources of information that might be of interest to you:
    http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=607464
    http://www.mythyroid.com/whythyroidcancer.html

Return to top