Distinct molecular profiles of indeterminate and malignant thyroid nodules in patients under 21 years of age.
In a large observational comparison of Afirma-tested thyroid nodules, samples from patients under 21 years showed enriched BRAF, DICER1, TSHR, RET, NTRK3, and ALK alterations, absent TERT promoter mutations, and distinct cell-cycle, ERK, angiogenesis, EMT, and differentiation signatures relative to adults.
Open original publication →What the AI sees
In a large observational comparison of Afirma-tested thyroid nodules, samples from patients under 21 years showed enriched BRAF, DICER1, TSHR, RET, NTRK3, and ALK alterations, absent TERT promoter mutations, and distinct cell-cycle, ERK, angiogenesis, EMT, and differentiation signatures relative to adults.
Research significance
The record demonstrates age-associated enrichment of potentially actionable RET/NTRK/ALK fusions and associated expression programs; it supports the hypothesis—but does not establish—that systematic molecular testing could identify younger patients for genotype-directed therapy or trials and that ERK, angiogenesis, or EMT-related biology may offer additional targets.
Source abstract
Although uncommon, thyroid nodules (TN) in pediatric and young adult patients carry higher malignancy risk and often present with a high burden of metastatic disease than adults. The molecular features underlying this distinct clinical behavior remain unclear. We analyzed Afirma Genomic Sequencing Classifier (GSC) data from 283,621 TN, comparing patients <21 and ≥21 years. Cytology (Bethesda), GSC benign (B) vs suspicious (S) calls, and Afirma Xpression Atlas (XA) variant/fusion profiles were evaluated in GSC-S and Bethesda V/VI samples. Genome-wide expression was used to derive pathway signatures and thyroid cancer-related scores: BRAF-RAS score (BRS), ERK, follicular and epithelial-to-mesenchymal transition (FMT, EMT) and thyroid differentiation scores (TDS). Among 2,397 patients <21 (median age 18.9; 81.4% female) and 281,224 adults ≥21 (median age 59.8; 77.1% female), <21 samples showed more Bethesda V/VI cytology (14.5% vs 5.0%; p<0.0001) and a lower GSC-B rate (43.5% vs 68.8%; p<0.0001). In GSC-S samples, total variant detection was higher in <21 (45.3% vs 37.4%), with enriched BRAF p.V600E, TSHR, and DICER1 variants, while HRAS variants were more common in adults (all p<0.01). Gene fusions involving RET, NTRK3 and ALK were enriched in <21 (14.5% vs 5.5%; p<0.0001). TERT promoter mutations were absent in <21 yrs GSC-S and Bethesda V/VI samples (vs 4.2% and 9.3% in adults). GSC-S <21 showed cell-cycle pathway enrichment. RET/NTRK/ALK-positive <21 demonstrated enrichment of angiogenesis and EMT pathways, higher ERK/EMT/FMT scores, and lower BRS/TDS scores vs genotyped-matched adults. These molecular differences provide mechanistic insight into the more invasive phenotype in pediatric and young adult TN.