Is there a link between parathyroid cancer and BHD?

A recent study investigated the genes that may cause parathyroid cancer. In this study, the researchers found the same genetic variants associated with BHD in some patients with parathyroid cancer. This blog will discuss the results and shed some light on if there is a link between the two conditions.

What is parathyroid cancer?

Parathyroid cancer is condition in which cancer cells form in the tissues of a parathyroid gland. It is a rare condition, but it recurs in at least 1 in every 2 people. This means for a large number of people, the condition may return after it has been treated. There is currently no approved systemic therapy for the condition. This is therapy that travels through the entire body instead of targeting one area. The high reoccurrence rate coupled with the lack of systemic therapy, supports the need to develop new effective treatments.

Parathyroid cancer has not been reported in BHD. However, non-cancerous BHD tumours have been seen in people with BHD.

Hunting for genes

The researchers analysed the genes of 17 patients with ‘sporadic’ parathyroid cancer. This is cancer that occurs in people who do not have a family history of that cancer.

Germline folliculin (FLCN) sequencing was performed in the 17 patients with sporadic parathyroid cancer. Mutations in the FLCN gene are associated with BHD. Germline sequencing is a type of DNA testing that looks for inherited mutations. The researchers found germline FLCN variant in three patients. Two of these patients were diagnosed with BHD. Consequently, the study presented the first recorded cases of parathyroid cancer in people with BHD.

The researchers also found somatic FLCN variants in two patients. Somatic mutations are changes in the DNA which occur after conception. In other words, they are not inherited. The two patients with somatic FLCN variants did not have any symptoms of BHD.

The researchers then analysed parathyroid non-cancerous tumours in 74 patients to look for FLCN variants. In this study, FLCN variants were not found in the 74 patients.

Why are these results important?

This study provides new information on if there is a possible link between parathyroid cancer and BHD. Firstly, FLCN mutations were found in people with parathyroid cancer. However, we do not know if BHD causes parathyroid cancer especially as it has been reported in so few people. It is possible that they developed parathyroid cancer by chance. Interestingly, although previously reported, no FLCN mutations were seen in the 74 people with non-cancerous parathyroid tumours in this study. These results point towards a clear need for further research.

To increase our understanding of BHD, it is crucial that we get more data. Last year, we launched the BHD syndrome international registry (BIRT). BIRT is a patient-reported database where people with BHD can upload information about their condition. The data can drive research and help answer questions. Take part in the registry now. Click here to email us with any questions.

We are sorry but this paper is not freely available. If you have any questions please contact us at contact@thebhdfoundation.org.