Protein Identified That May Predict Thyroid Cancer Recurrence

A protein called Programmed Death Ligand 1 (PD-L1), can help to predict which thyroid cancer patients will most likely have a recurrence of the disease.

More than 80% of patients diagnosed with thyroid cancer have a type called papillary thyroid cancer, which usually grows on only one side of the thyroid gland and most of these patients are women and some have been exposed to ionizing radiation.

Scientists at the US National Institutes of Health (NIH; Bethesda, MD, USA) study the role of a specific protein, PD-L1, which is normally present in the body's immune system to assist with communication between immune cells and help regulate immune response. PD-L1 is also present in some papillary thyroid cancer cells, and may actually help to protect the tumor from the immune system. This protection may then allow the cancer to grow and eventually spread, often to the lymph nodes.

The scientists examined resected stored tumor samples from more than 200 patients. They used gene expression microarrays to collect data on more than 30,000 genes in each sample - including the PD-L1 (also known as CD274 molecule) gene. They were able to confirm their findings by focusing on PD-L1 expression in each sample. The final step was to compare PD-L1 levels with medical records of how the patients fared.

Ryan J. Ellis, BS, a fourth-year medical student at the Perelman School of Medicine (Philadelphia, PA, USA) and a coauthor of the study said, “In this cohort of patients, we found that those with high levels of PD-L1 were about twice as likely to have a recurrence as patients with normal PD-L1 levels. The real potential is being able to differentiate those who may have a more aggressive type of thyroid cancer by the time of surgical treatment. Surgeons could potentially look at the patient's PD-L1 expression following biopsy or immediately after resection to see if the patient is more likely to have a recurrence." The study was presented at the Clinical Congress of the American College of Surgeons held October 6-10, 2103, in Washington DC, USA.

Related Links:
US National Institutes of Health
Perelman School of Medicine