Molecular genetic analysis of thyroid carcinomas in pediatric and adolescent patients

Thyroid nodules are rare in pediatric and adolescent patients, but they are at greater risk of malignancy than adult patients. Thyroid carcinomas are the most common endocrine malignancy and their incidence is increasing. Although there are several types of thyroid carcinoma, 90% of cases in pediatric and adolescent patients are papillary thyroid carcinomas (PTCs). The aim of this study was to analyze a large cohort of PTCs from pediatric and adolescent patients, determine their genetic cause, and correlate the findings with clinical pathological data. Another aim was to characterize the most frequent findings and compare them with a cohort of adult patients with thyroid carcinoma positive for the same mutation. The final objective was to optimize a suitable methodology for detecting the most common findings in pediatric and adolescent patients for routine use. Thyroid tumor tissue samples were examined using molecular genetic methods, mostly using next-generation sequencing and real-time PCR analysis. We found that fusion genes were the most common cause of PTC in pediatric and adolescent patients, detected in 56% of patients. In total, 20 different types of fusion genes were identified, some of which have not been previously described in the literature. The fusion genes included the oncogenes...