The Somatic Mutational Landscape of Thyroid Cancer in Patients with Germline PTEN Mutations

PTEN hamartoma tumor syndrome (PHTS) is associated with a high rate of thyroid cancer and benign thyroid disease, yet nothing is known of the genomic landscape of PHTS-associated thyroid tumors. In this study, exome sequencing was performed on 58 thyroid tumors (28 cancers, 30 benign nodules) from 19 patients with PHTS, sequenced in tumor-normal pairs. Somatic variant calling was utilized to determine the somatic mutational landscape of thyroid tumors in this population. This was then compared to the known mutational landscape of sporadic thyroid cancer in the general population using sequencing data from The Cancer Genome Atlas. The primary finding of the study was that PHTS-associated thyroid tumors had a unique genomic landscape, including a high frequency of second-hit somatic PTEN alterations compared to the sporadic thyroid tumors. Additionally, PHTS-associated thyroid cancers were found to have somatic alterations in BRAF, RAS family members, and genes associated with DNA double stranded break repair. Data available through dbGAP will include tumor BAM files for each tumor, normal BAM files for each patient, and MAF files for PHTS-associated thyroid cancer and PHTS associated benign thyroid nodules.]]>
Inclusion criteria: Patients diagnosed with PTEN hamartoma tumor syndrome, defined by a pathogenic or likely pathogenic germline PTEN variant, who underwent thyroid surgery with a final pathology of thyroid cancer. From available tissue, all cancers were selected for sequencing, and up to three benign nodules per patient were selected.Exclusion criteria: Patients that did not have blocks or tissue available from surgery. ]]>