Department of Pathology, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan Province, China.
Department of Pathology and Laboratory Medicine, Loyola University Medical Center, IL60153, USA.
Pathol Res Pract. 2022 Mar;231:153790. doi: 10.1016/j.prp.2022.153790. Epub 2022 Jan 29.
Secretory carcinoma of the breast (SCB) is a rare low-grade often triple-negative breast carcinoma. We aim to analyze the pathological and molecular features of 21 SCBs, especially the SCBs with axillary lymph node metastasis.
The clinicopathological characteristics of 21 SCBs were reviewed. Breast biomarkers, Pan-TRK and ETV6 break, and ETV6-NTRK3 fusion were performed on all cases. Next-Generation Sequencing (NGS) was performed on two cases with lymph node metastasis.
21 SCBs consisted of 2 men and 19 women aged 5～73 years (median 43 years), with a mean 2.1 cm (range 0.5～3.5 cm) tumor size. 90.1% (19/21) cases had mixed microcystic, solid, tubular, and papillary patterns. Pan-TRK and S100 are positive in 95% (20/21) and 90% (19/21) of cases, respectively. Tumor markers ER, PR, and HER2 expressions were 62% (13/21), 33% (7/21), and 0% (0/21). All cases showed ETV6 (21/21) rearrangement and ETV6-NTRK3 (11/11) fusion. 57% (12/21) of the cases had a balanced translocation and 38% (8/21) with unbalanced signals of ETV6. There was no clinical difference between balanced and unbalanced translocations in histological morphology and other prognosis factors. Furthermore, one case (#4) had a duplication of the ETV6 gene and presented axillary lymph node metastasis. NGS analysis revealed simple genomes, low tumor mutation burden, stable microsatellite sites, and single nucleotide polymorphism (SNP) heterozygous mutation in both SCBs with nodal metastasis.
SCB is an indolent invasive carcinoma, even the cases with axillary lymph node metastasis, presenting simple genomes. Duplication of ETV6 cases may indicate lymph node metastasis.
乳腺分泌性癌（SCB）是一种罕见的低级别、常为三阴性乳腺癌。本研究旨在分析 21 例 SCB 的病理和分子特征，尤其是伴有腋窝淋巴结转移的 SCB。
回顾性分析 21 例 SCB 的临床病理特征。所有病例均进行乳腺标志物、泛 TRK 和 ETV6 断裂、ETV6-NTRK3 融合检测。对 2 例有淋巴结转移的病例进行下一代测序（NGS）分析。
21 例 SCB 患者中包括 2 例男性和 19 例女性，年龄 5～73 岁（中位年龄 43 岁），肿瘤大小平均为 2.1cm（范围 0.5～3.5cm）。90.1%（19/21）的病例有混合微囊状、实体状、管状和乳头状形态。95%（20/21）和 90%（19/21）的病例分别表达泛 TRK 和 S100。肿瘤标志物 ER、PR 和 HER2 的表达率分别为 62%（13/21）、33%（7/21）和 0%（0/21）。所有病例均显示 ETV6（21/21）重排和 ETV6-NTRK3（11/11）融合。57%（12/21）的病例有平衡易位，38%（8/21）的病例有 ETV6 信号的不平衡。在组织形态学和其他预后因素方面，平衡和不平衡易位之间没有临床差异。此外，1 例（#4）存在 ETV6 基因的重复，表现为腋窝淋巴结转移。NGS 分析显示，在伴有淋巴结转移的 2 例 SCB 中，基因组简单，肿瘤突变负担低，微卫星稳定，单核苷酸多态性（SNP）杂合性突变。
SCB 是一种惰性浸润性癌，即使是伴有腋窝淋巴结转移的病例，也表现出简单的基因组。ETV6 重复的病例可能预示着淋巴结转移。
