雌激素受体 (ER) 阴性、孕激素受体 (PR) 阴性和人表皮生长因子受体 2 (HER2) 阴性的乳腺癌称为三阴性乳腺癌 (TNBC)。由于缺乏特异性治疗靶点，细胞毒性化疗仍然是 TNBC 的首选治疗方法。 TNBC 并未根据治疗靶点进行分类，但最近，包括免疫检查点抑制剂和聚（腺苷二磷酸核糖）聚合酶抑制剂在内的靶向疗法的开发引起了人们的关注。本研究旨在检查一种新的靶向 TNBC 分类，通过根据乳腺癌 1 (BRCA1) 样以及 HER2、程序性死亡配体 1 (PD-L1) 的蛋白表达对 TNBC 进行分类，进一步促进靶向治疗。雄激素受体（AR）、细胞角蛋白5/6和表皮生长因子受体（EGFR）。我们招募了17名原发性TNBC患者，他们没有接受术前化疗，并于2018年1月1日至2018年1月1日期间在日本神户大学医院接受了手术。 2019 年 7 月 31 日。对肿瘤标本进行免疫组织化学染色，同时使用多重连接依赖性探针扩增 (MLPA) 分析进行 BRCAness 测试。 BRCAness 评分 0.5 或更高被认为是 BRCA1 样。肿瘤被分类为 HER2 低（免疫组织化学评分 1 或 2 且 FISH 阴性）、PD-L1 阳性、AR 阳性或 BRCA1 样。在 11 个 (64.7%)、4 个 (23.5%)、6 个 (35.3%) 和 6 个 (35.3%) 样本中检测到 HER2 低、PD-L1 阳性、AR 阳性和 BRCA1 样。仅一名患者的肿瘤无法归入这些类别中的任何一类。几乎所有 TNBC 病例都可以根据可治疗的靶点进行分类。版权所有 © 2023 国际抗癌研究所 (Dr. George J. Delinasios)，保留所有权利。

Breast cancer that is estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor-2 (HER2)-negative is termed triple-negative breast cancer (TNBC). Cytotoxic chemotherapy remains the first choice of treatment against TNBC due to lack of specific therapeutic targets. TNBC is not classified based on therapeutic targets, but recently, the development of targeted therapies - including immune checkpoint inhibitors and poly (adenosine diphosphate-ribose) polymerase inhibitors - has gained attention. This study aimed to examine a novel target-oriented TNBC classification to further facilitate targeted therapy by classifying TNBC based on the breast cancer 1 (BRCA1)-like as well as the protein expression of HER2, programmed death ligand 1 (PD-L1), androgen receptor (AR), cytokeratin 5/6, and epidermal growth factor receptor (EGFR).We enrolled 17 patients with primary TNBC who did not receive preoperative chemotherapy and underwent surgery at the Kobe University Hospital, Japan, between January 1, 2018, and July 31, 2019. Immunohistochemical staining was performed on tumor specimens, while a BRCAness test was performed using multiplex ligation-dependent probe amplification (MLPA) analysis. A BRCAness score 0.5 or higher was considered BRCA1-like.Tumors were classified as HER2-low (immunohistochemistry score 1+ or 2+ and FISH negative), PD-L1 positive, AR positive, or BRCA1-like. HER2-low, PD-L1 positive, AR positive, and BRCA1-like were detected in 11 (64.7%), 4 (23.5%), 6 (35.3%), and 6 (35.3%) samples. The tumor of only one patient could not be classified into any of these categories.Almost all TNBC cases can be classified according to treatable targets.Copyright © 2023 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.