Institute of Pathology and Forensic Medicine, Military Medical Academy.
Ipatimup Diagnostics, Institute of Molecular Pathology and Immunology of Porto University, Ipatimup, Porto, Portugal.
Bosn J Basic Med Sci. 2022 Feb 1;22(1):54-63. doi: 10.17305/bjbms.2021.6181.
The EWSR1 rearrangements with unknown genes were detected in a high percentage of classic variants of papillary thyroid carcinoma. The small-cell carcinoma of the thyroid with Ewing family tumor elements (CEFTE) typically presents with EWSR1-FLI1 rearrangement suggesting the possible role of EWSR-FLI1 translocation in the loss of thyroid differentiation and acquisition of a small-cell phenotype. In order to determine the frequency and association of EWSR1 rearrangements, particularly the EWSR1-FLI1 fusion with clinicopathological features of papillary thyroid microcarcinoma (m-PTC) and the presence of small cells, we analyzed a series of 99 m-PTCs using the fluorescence in situ hybridization method. Ninety cases (90.9%) of m-PTC were positive for small cells. This group of m-PTC has shown more often invasive growth, lymphatics invasion, and moderate/extended intratumoral fibrosis. Three cases out of 99 were inconclusive for EWSR1 rearrangement. Eighty-nine (92.7%) and twenty-seven (28.1%) out of 96 m-PTC cases were positive for EWSR1 rearrangement and EWSR1-FLI1 fusion, respectively. m-PTC with classical architectural pattern presented more frequently with EWSR1 rearrangement relative to m-PTC with other patterns (p = 0.005). Other clinicopathological features were not related to the presence of EWSR1 rearrangement or EWSR1-FLI1 fusion. The percentage of small cells present significantly correlated with the percentage of cells positive for EWSR1-FLI1 fusion (p = 0.05) and EWSR1 rearrangement (p <0.001). EWSR1-FLI1 fusion is not rare in m-PTC and it is associated with the acquisition of small-cell phenotype. The EWSR1 gene rearrangement is a frequent event in m-PTC and is related to the classical pattern of m-PTC.
EWSR1 重排与未知基因在经典型甲状腺乳头状癌的多个变体中被检测到。具有尤文氏家族肿瘤成分的甲状腺小细胞癌（CEFTE）通常表现为 EWSR1-FLI1 重排，提示 EWSR-FLI1 易位可能在甲状腺分化丧失和获得小细胞表型方面发挥作用。为了确定 EWSR1 重排的频率和关联，特别是 EWSR1-FLI1 融合与甲状腺微小乳头状癌（m-PTC）的临床病理特征和小细胞的存在，我们使用荧光原位杂交法分析了一系列 99 例 m-PTC。90 例（90.9%）m-PTC 有小细胞存在。这组 m-PTC 更常表现为侵袭性生长、淋巴管侵犯和中/广泛的肿瘤内纤维化。99 例中有 3 例 EWSR1 重排结果不确定。96 例 m-PTC 中有 89 例（92.7%）和 27 例（28.1%）为 EWSR1 重排和 EWSR1-FLI1 融合阳性。经典结构模式的 m-PTC 比其他模式的 m-PTC 更常出现 EWSR1 重排（p = 0.005）。其他临床病理特征与 EWSR1 重排或 EWSR1-FLI1 融合的存在无关。小细胞的存在百分比与 EWSR1-FLI1 融合阳性细胞的百分比（p = 0.05）和 EWSR1 重排（p <0.001）显著相关。EWSR1-FLI1 融合在 m-PTC 中并不罕见，与获得小细胞表型相关。EWSR1 基因重排在 m-PTC 中是一种常见事件，与 m-PTC 的经典模式相关。
