Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Histopathology. 2024 Sep;85(3):503-509. doi: 10.1111/his.15276. Epub 2024 Jul 8.
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.
腺样囊性癌是三阴性乳腺癌的一种罕见亚型。与其他三阴性乳腺癌相比，这些低级别肿瘤通过单纯乳房切除术治疗，预后极好。实体型腺样囊性癌具有基底细胞样特征，在形态学上难以与其他三阴性乳腺癌区分。乳腺腺样囊性癌表现出 MYB 蛋白过表达，可通过免疫组织化学（IHC）检测到。
我们比较了实体型腺样囊性癌与其他三阴性乳腺癌中 MYB 的 IHC 表达。
我们对 210 例三阴性乳腺癌样本进行了 IHC 染色，包括实体型腺样囊性癌（n=17）、化生性乳腺癌（n=44）、基底细胞样三阴性乳腺癌（n=21）和其他三阴性浸润性导管癌（n=128）。我们将 MYB 的核染色分类为弥漫/强（3+）、局灶中度（2+）、局灶弱（1+）或无（0）。
所有 17 例实体/基底样腺样囊性癌均表现出 3+MYB 表达。21 例实体/基底样三阴性乳腺癌中，1 例（5%）为 2+表达，7 例（33%）为 1+表达，13 例（62%）为 0 表达。44 例化生性癌病例中，39 例（89%）无（0）染色，另外 5 例为局灶弱（1+）或中度（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%）表现为局灶弱（1+）或中度（2+）染色。
我们的研究仅在实体/基底样腺样囊性癌中发现弥漫/强 MYB 染色（3+）。因此，我们建议对具有实体/基底样形态的三阴性乳腺癌常规进行 MYB IHC 染色，以提高诊断准确性。
