Clinicopathological Features of and Fusions in Thyroid Cancer: A Single-Center Retrospective Cohort Study in a Chinese Population.

The rearranged during transfection () proto-oncogene fusion is common in papillary thyroid cancer (PTC), varying across ethnic groups. However, comprehensive comparisons of fusion types are limited. This study aims to identify predominant fusions and analyze their clinicopathological characteristics in a cohort of Chinese thyroid cancer cases. This single-center retrospective cohort study analyzed thyroid cancer data, utilizing next-generation sequencing on formalin-fixed, paraffin-embedded tissue samples. Detailed clinicopathological data of thyroid cancer cases with fusions were collected. Among 2300 thyroid cancer cases, fusions were exclusively found in PTC or differentiated high-grade thyroid carcinoma (DHGTC) cases (2234 cases), absent in other types (66 cases). Of the 2234 PTC or DHGTC cases, 113 (5.06%) exhibited fusions, including 100 primary cases. Coiled-coil domain containing 6 ( fusions predominated (78.0%, 78/100), with nuclear receptor coactivator 4 ( fusions representing 22.0% (22/100). fusions were more prevalent in patients aged 45 years and older (54.5% vs. 28.2%, 0.021) and DHGTC cases ( < 0.05) and associated with higher rates of lymph node metastases (90.9% vs. 67.9%, 0.032). fusion exhibited a higher prevalence of Hashimoto's thyroiditis (HT) (67.9% vs. 22.7%, < 0.001) and elevated thyroglobulin antibody levels (14.11 [1.86-174.32] IU/mL vs. 2.01 [1.14-15.41] IU/mL, 0.018). Moreover, fusion predominantly occurred in classical PTC (56.4%, 44/78) and infiltrative follicular PTC (17.9%, 14/78), whereas fusion was more frequent in classical PTC (36.4%, 8/22), solid PTC (27.3%, 6/22), and DHGTC (27.3%, 6/22). fusions with compound mutations were associated with older age (≥45 years) and bilateral thyroid involvement. Follow-up data showed a higher recurrence rate in the fusion group compared with the mutation group (5.0% vs. 0.0%, 0.018). Although the group showed a numerically higher recurrence rate compared with (9.1% vs. 3.8%), this difference was not statistically significant ( 0.559). fusions are specific to PTC or DHGTC cases among Chinese thyroid cancer cases. and fusions exhibited distinct clinicopathological features, with being more aggressive.