美国临床肿瘤学会和美国病理学家学会 HER2 指南建议对核心活检中 HER2 阳性的大多数 1 级乳腺癌进行重复检测。本研究旨在评估重复 HER2 检测的价值以及 HER2 阳性 1 级癌症的组织学特征。对术前未接受全身治疗超过 5 年的患者进行了 1 级癌症 HER2 结果的病例系列研究。年期间。 HER2 阳性癌症进行了组织学检查。 12 例 HER2 阳性癌症最初报告为 1 级。经审查，其中 2 例被重新分类为 2 级。其余 10 例癌症占 508 例 1 级癌症的 2%。还研究了其他年份的 8 例 HER2 阳性 1 级癌症。与 HER2 阴性 1 级癌症相比，HER2 阳性癌症更常具有明显的核多形性（50% 对 6%），雌激素受体阴性（17% 对 0.8%）和孕激素受体阴性（28% 对 8%）更常见。核心活检中 HER2 为 3 的 6 个癌症在重复评估中也为 3。在核心活检中扩增的 7 个癌症中，有 5 个在切除中也呈 HER2 阳性。HER2 阳性 1 级癌症并不常见，与 HER2 阴性相比，更常见的是具有明显的核多形性，并且缺乏雌激素受体和孕激素受体表达1 级癌。在重复检测的 13 个肿瘤中，有 11 个肿瘤的核心活检结果为 HER2 阳性。© 2024 John Wiley

The American Society of Clinical Oncology and College of American Pathologists HER2-guidelines recommend repeat testing for most grade 1 mammary carcinomas that are HER2-positive in the core biopsy. This study aimed to assess the value of repeat HER2-testing and the histological features of HER2-positive grade 1 carcinomas.A case-series of HER2-results of grade 1 carcinomas was conducted of patients with no pre-operative systemic treatment over a 5-year period. HER2-positive carcinomas had histological review. Twelve HER2-positive carcinomas were initially reported as grade 1. On review, two were reclassified as grade 2. The remaining 10 carcinomas represented 2% of the 508 grade 1 carcinomas. Eight HER2-positive grade 1 carcinomas from other years were also studied. HER2-positive carcinomas more often had marked nuclear pleomorphism (50 versus 6%) and were more often oestrogen receptor-negative (17 versus 0.8%) and progesterone receptor-negative (28 versus 8%) compared with HER2-negative grade 1 carcinomas. Six carcinomas that were HER2 3+ in the core biopsy were also 3+ on repeat assessment. Five of seven carcinomas that were 2+ amplified in the core biopsy were also HER2-positive in the excision.HER2-positive grade 1 carcinomas are uncommon, and more often have marked nuclear pleomorphism and lack oestrogen receptor and progesterone receptor expression compared with HER2-negative grade 1 carcinomas. A HER2-poitive result in the core biopsy was confirmed in 11 of 13 tumours that had repeat testing.© 2024 John Wiley & Sons Ltd.