Researchers have identified two unique biomarkers that show promise for monitoring patients who have received treatment for papillary thyroid cancer (PTC), according to a study recently published in the new open access Journal of the Endocrine Society.
The team, led by Sebastiano Filetti, MD, of the Dipartimento di Medicina Interna e Specialitá Mediche, “Sapienza” Universitá di Roma, point out that serum thyroglobulin (Tg) is the main biomarker used to detect persistent or recurring thyroid cancer, but “its specificity is limited in the presence of anti-Tg autoantibodies and residual normal thyroid tissue.” The residual normal thyroid tissue is especially a concern, showing up more often because of the decline in total thyroidectomy procedures. “Consequently, the search is on for new, more specific tumor biomarkers to ensure optimal postoperative follow-up of today’s thyroid cancer patients,” the authors write.
The researchers wanted to identify thyroid tumor-associated microRNAs (miRNAs) in the hopes of finding some with potential for development as unique biomarkers to detect PTC recurrence. They measured expression of 754 miRNAs in serum from 11 patients with PTC before and 30 days after thyroidectomy. The investigators then re-evaluated major candidates using an absolute quantitative polymerase chain reaction analysis in an independent cohort of patients with PTC (n = 44) or benign nodules (BN, n = 19) and healthy controls (HC, n = 20). “The 2 miRNAs most significantly associated with thyroid tumors were then assessed in matched serum samples (before and 30 days and 1 to 2 years after surgery) from the 20 PTC patients with complete follow-up datasets and results correlated with American Thyroid Association (ATA) responses to therapy,” the authors write.
The researchers found eight promising miRNAs, but two — miR-146a-5p and miR-221-3p – stood out as the most promising candidates. “Serum levels of both miRNAs after 1 to 2 years of follow-up were consistent with ATA responses to therapy in all patients, including 2 with structural evidence of disease whose Tg assays remained negative (<1 ng/mL),” they write.
Based on these results, the authors conclude that “serum levels of miR-146a-5p and miR-221-3p might one day be used as complementary biomarkers for the early noninvasive detection of persistent/recurrent PTC, particularly in the expanding population of patients undergoing more conservative treatment of these tumors.” They also note that studies to validate these findings are already underway.