腺样囊性癌是三阴性乳腺癌的一种罕见亚型。这些低级别肿瘤可通过简单的乳房切除术进行治疗，与其他三阴性乳腺癌相比，预后良好。实体变异腺样囊性癌具有基底细胞样特征，很难在形态学上与其他三阴性乳腺癌区分开。乳腺腺样囊性癌表现出MYB蛋白过度表达，可以通过免疫组织化学（IHC）检测到。我们将实性变异腺样囊性癌中MYB的IHC表达与其他三阴性乳腺癌中的表达进行比较。我们对210个样本进行了IHC染色三阴性乳腺癌，包括实体变异腺样囊性癌（n = 17）、化生性乳腺癌（n = 44）、基底样三阴性乳腺癌（n = 21）和其他三阴性浸润性导管癌（ n = 128）。我们将 MYB 的核染色分为弥漫/强 (3)、局灶中度 (2)、局灶弱 (1) 或无 (0)。所有 17 例实性/基底样腺样囊性癌病例均表现出 3 个 MYB 表达。在 21 例实体/基底样三阴性乳腺癌中，1 例 (5%) 表达 2，7 例 (33%) 表达 1，13 例 (62%) 表达 0。 44例化生癌病例中，39例（89%）无（0）染色，其余5例有局灶性弱（1）或中（2）染色。在128例三阴性浸润性导管癌病例中，92例（72%）无（0）染色，36例（28%）呈现局灶性弱（1）或中度（2）染色。我们的研究显示弥漫/强MYB仅在实性/基底样腺样囊性癌中染色 (3)。因此，我们建议对具有实性/基底样形态的三阴性乳腺癌进行常规 MYB IHC 染色，以提高诊断准确性。© 2024 John Wiley

Adenoid cystic carcinoma is a rare subtype of triple-negative breast carcinoma. These low-grade tumours, which are treated by simple mastectomy and have an excellent prognosis compared to other triple-negative breast carcinomas. Solid-variant adenoid cystic carcinomas have basaloid features and are difficult to distinguish morphologically from other triple-negative breast cancers. Breast adenoid cystic carcinoma exhibits MYB protein overexpression, which can be detected by immunohistochemistry (IHC).We compared the IHC expression of MYB in solid-variant adenoid cystic carcinoma with that in other triple-negative breast cancers.We conducted IHC staining of 210 samples of triple-negative breast cancers, including solid-variant adenoid cystic carcinoma (n = 17), metaplastic breast carcinoma (n = 44), basaloid triple-negative breast cancer (n = 21), and other triple-negative invasive ductal carcinoma (n = 128). We classified nuclear staining of MYB as diffuse/strong (3+), focal moderate (2+), focal weak (1+), or none (0).All 17 solid/basaloid adenoid cystic carcinoma cases exhibited 3+ MYB expression. Of the 21 solid/basaloid triple-negative breast cancers, one (5%) had 2+ expression, seven (33%) 1+ expression, and 13 (62%) 0 expression. Of the 44 metaplastic carcinoma cases, 39 cases (89%) had no (0) staining, and the other five cases had focal weak (1+) or moderate (2+) staining. Among the 128 triple-negative invasive ductal carcinoma cases, 92 cases (72%) had no (0) staining, 36 cases (28%) exhibited focal weak (1+) or moderate (2+) staining.Our study revealed diffuse/strong MYB staining (3+) only in solid/basaloid adenoid cystic carcinomas. Thus, we recommend routine MYB IHC staining in triple-negative breast carcinoma with solid/basaloid morphology to improve diagnostic accuracy.© 2024 John Wiley & Sons Ltd.