Department of Pathology and Laboratory Medicine, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Lu, Guangzhou, 510080, People's Republic of China.
Department of Breast Cancer, Cancer Center, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, People's Republic of China.
Breast Cancer Res Treat. 2019 May;175(1):51-57. doi: 10.1007/s10549-019-05148-5. Epub 2019 Feb 2.
Human epidermal growth factor receptor 2 (HER2, ERBB2) is a valuable prognostic and predictive biomarker in breast cancer. Accurate assessment of HER2 status is essential in selecting the patients with invasive breast cancer who will likely response to HER2-targeted therapies. Some major modifications in the diagnostic recommendation for fluorescence in situ hybridization (FISH) have been made in the updated 2018 American Society of Clinical Oncology (ASCO)/College of American Pathologist (CAP) guideline. According to the revised guideline, concomitant IHC assays are required to arrive at the most accurate HER2 status designation after HER2 FISH equivocal results; however, little is known about its influence on the clinical practice of pathologist. The purpose of this study was to evaluate the impact of the revised 2018 ASCO/CAP guidelines on the HER2 status designation.
We retrospectively reviewed the HER2 FISH testing results from 2233 cases of invasive breast cancer between January 2014 and December 2017. Concomitant immunohistochemistry (IHC) were performed on the same tissue blocks that were used for the FISH testing.
Compared to the 2013 guidelines, the HER2 status in 183 (8.2%) cases were re-defined when reassessed by the 2018 guidelines. Among these 183 cases, 175 equivocal cases according to the 2013 guideline were re-defined as HER2 negative (n = 173) or HER2 positive (n = 2). Eight previously classified as HER2 positive cases were converted to negative in the 2018 scheme, all of which were with HER2 IHC scores of 1+ or 2+. The number of cases in the negative category was 1705 according to the 2018 guidelines as opposed to 1524 by the 2013 guidelines.
The updated 2018 ASCO/CAP guidelines eliminated the FISH equivocal category, which can be attributed to reflex HER2 IHC, and partly ease the dilemma for clinical practice. Reflex IHC for FISH equivocal cases is of prime importance; furthermore, HER2 FISH results were converted from positivity to negativity based on the concomitant IHC results in a small percentage of cases. In all, implementation of the 2018 ASCO/CAP guidelines provides much clearer instructions and recommendations for the HER2 status designation, and thus reduces the risk of misdiagnosis.
人类表皮生长因子受体 2（HER2，ERBB2）是乳腺癌有价值的预后和预测生物标志物。准确评估 HER2 状态对于选择可能对 HER2 靶向治疗有反应的浸润性乳腺癌患者至关重要。在更新的 2018 年美国临床肿瘤学会（ASCO）/美国病理学家学院（CAP）指南中，对荧光原位杂交（FISH）的诊断建议进行了一些重大修改。根据修订后的指南，在 HER2 FISH 结果不确定的情况下，需要同时进行免疫组织化学（IHC）检测，以得出最准确的 HER2 状态指定；然而，病理学家对其对临床实践的影响知之甚少。本研究旨在评估修订后的 2018 年 ASCO/CAP 指南对 HER2 状态指定的影响。
我们回顾性分析了 2014 年 1 月至 2017 年 12 月间 2233 例浸润性乳腺癌的 HER2 FISH 检测结果。对用于 FISH 检测的同一组织块同时进行免疫组化（IHC）检测。
与 2013 年指南相比，当按照 2018 年指南重新评估时，183 例（8.2%）HER2 状态被重新定义。在这 183 例中，175 例 2013 年指南定义为不确定的病例被重新定义为 HER2 阴性（n=173）或 HER2 阳性（n=2）。8 例先前分类为 HER2 阳性的病例在 2018 年方案中被转换为阴性，所有这些病例的 HER2 IHC 评分均为 1+或 2+。根据 2018 年指南，阴性病例数为 1705 例，而根据 2013 年指南为 1524 例。
更新后的 2018 年 ASCO/CAP 指南消除了 FISH 不确定类别，可以归因于反射 HER2 IHC，部分缓解了临床实践的困境。FISH 不确定病例的反射 IHC 至关重要；此外，在一小部分病例中，根据伴随的 IHC 结果，HER2 FISH 结果从阳性转换为阴性。总之，实施 2018 年 ASCO/CAP 指南为 HER2 状态指定提供了更清晰的说明和建议，从而降低了误诊的风险。
