The genetic landscape of benign thyroid nodules revealed by whole exome and transcriptome sequencing.

The genomic alterations for benign thyroid nodule, especially adenomatoid nodule, one of the most common types of hyperplasia lesion, are ill-studied. Here, we show whole-exome sequencing and/or transcriptome sequencing data on adenomatoid nodules with or without coincidental papillary thyroid carcinoma (PTC). Somatic mutation of BRAF (22/32) is only detected in PTC, while mutations in SPOP (4/38), ZNF148 (6/38) and EZH1 (3/38) are found enriched in adenomatoid nodule. In an expanded cohort of adenomatoid nodule (n=259) mutually exclusive SPOP, EZH1 and ZNF148 mutations are identified in 24.3% of them. Adenomatoid nodules show very few overlapped mutations and distinct gene expression patterns with their coincidental PTC. Phylogenetic tree analysis uncovers that PTCs evolved independently from their matched benign nodules. Our findings reveal that benign nodules possess a unique molecular signature that differs from PTC and provide genomic evidence for the conventional belief that PTC and benign nodules have independent origin.