The Genetic Landscape of Thyroid Cancer

Young Joo ParkKorea (Republic of) Speaker Translating the Genetic Landscape of Thyroid Cancer to Precision Diagnosis and TherapyThyroid cancer is characterized by a relatively low mutational burden compared with other solid tumors, with recurrent alterations mainly involving BRAF, RAS, and various fusion genes. Several novel driver candidates have also been identified through next-generation sequencing studies. The frequency and pattern of these genomic alterations differ across thyroid cancer subtypes and are often associated with distinct histopathological phenotypes, providing valuable clues for differential diagnosis. Moreover, molecular subtypes defined by driver mutations are closely linked to tumor biology and clinical behavior, allowing more accurate prediction of disease aggressiveness and prognosis. Most differentiated thyroid cancers (DTCs) harbor a single dominant driver alteration; however, acquisition of additional mutations such as TERT promoter, tumor suppressor genes, or PI3K–AKT pathway alterations may lead to dedifferentiation and progression to aggressive or metastatic disease. Advances in our understanding of these genetic alterations have refined the pathological classification of thyroid cancer and enabled improved prognostication, treatment selection, and follow-up strategies. Importantly, the identification of actionable genetic alterations—including RET and NTRK fusions, as well as BRAF mutations—has revolutionized therapeutic approaches. Targeted agents such as selpercatinib, pralsetinib, larotrectinib, and entrectinib demonstrate substantial clinical efficacy with fewer adverse events than multikinase inhibitors, while dabrafenib plus trametinib has shown marked benefit in anaplastic thyroid cancer. With multiple targetable mutations being uncovered, incorporating comprehensive genomic testing into the diagnostic workflow is essential to guide precision therapy for patients with thyroid cancer.