Novel gene classifier identifies benign thyroid nodules
SAN FRANCISCO — Researchers from Chile have developed a novel predictive gene assay that accurately and reliably diagnoses benign thyroid nodules. According to Hernan Gonzalez, MD, PhD, associate professor at the Pontifical Catholic University of Chile in Santiago, who presented the findings, the new “signature” could help identify those patients who do not require surgery.
“The aim of this work was to develop a suitable test for point-of-care diagnosis that could accurately rule out the presence of cancer in thyroid nodules,” he said during his presentation.
Eighteen genes were pre-selected from a literature search of potential biomarkers pointing to papillary thyroid cancer (PTC). Gonzalez and colleagues used real-time PCR to estimate the differential expression of the genes, and then developed new software to build an algorithm to integrate the genes to construct the classifier.
“When you develop a classifier, it has 3 stages: you train your classifier, you teach it to learn how to identify different gene profiles — in this case, cancer or not cancer. Then, you want to test it with a different independent cohort of patients, and finally you want to validate it.”
Gonzalez presented results from the first two phases.
Thyroid nodule samples were obtained from surgical specimens of 110 patients; 63 nodules were cancerous and the remaining nodules were benign. Sensitivity of the novel signature, which uses 10 genes, was 93%, with a negative predictive value of 96%. Using samples from an additional 105 patients, 38% of whom had cancer, the negative predictive value of the signature was maintained.
Researchers then used fine needle aspiration (FNA) samples from 100 patients, 23 of whom had cancer, and determined that the performance of the gene signature was maintained, with a 98% negative predictive value.
“In first two stages of training and testing we have a very predictive test. Because it only uses 10 genes it could potentially be used as a kit,” Gonzalez concluded. “We’ve built a new test that accurately rules out the presence of cancer in thyroid nodules … the clinical validation in indeterminate thyroid nodules is in progress today.” – by Stacey L. Adams
For more information:
Gonzales HE. #FP14-1. Presented at: The Endocrine Society Annual Meeting and Expo; June 15-18, 2013; San Francisco.
Disclosure: The researchers report no relevant financial disclosures.