摘要目的:探讨《乳腺癌HER2检测指南（2019版）》对HER2基因扩增状态的检测结果影响及其临床意义。方法:根据2014版《乳腺癌HER2检测指南》判读标准选取浙江省台州恩泽医疗中心病理学部2013—2019年所有免疫组织化学（IHC）检测HER2不确定（2+）并行荧光原位杂交（FISH）技术检测的浸润性乳腺癌548例，运用2019版指南对IHC结果和HER2/CEPl7双探针FISH检测结果进行重新评判并分组。结果:548例IHC HER2 2+的浸润性乳腺癌中，按照2014版检测指南，FISH检测结果为HER2阳性96例（17.52%）、不确定81例（14.78%）、阴性371例（67.70%）；而根据新的2019版检测指南评判，IHC检测有10例（1.82%）被判读为1+，FISH检测结果第2组2例直接判为阴性，第4组原本不确定的病例也均判为阴性，最终548例FISH检测结果为HER2阳性94例（17.15%）、阴性454例（82.85%）。结论:应用2019版指南后，IHC HER2 2+数量略有下降，FISH检测结果因为第2组和第4组的病例解释发生变化，导致HER2阳性率略有下降，从而对2014版本判定的不确定病例进行了重新分类。总体来说， 新版指南更加合理、可操作性更好。

abstractsO bjective To understand the effects and clinical significance of the 2019 guidelines for the human epidermal growth factor receptor 2 (HER2) detection. Methods:According to the 2014 guidelines, 548 cases of invasive breast cancer with equivocal HER2 (2+) detected by immunohistochemistry (IHC) in Taizhou Enze Medical Center, Zhejiang Province, China from 2013 to 2019 were selected. The results of IHC and HER2/CEPl7 double-probe were reevaluated and divided into groups according to the 2019 guidelines for the comparative analysis.Results:Among the 548 IHC HER2 (2+) invasive breast cancers, the number of positive, equivocal and negative cases for HER2 were 96 (17.52%), 81 (14.78%) and 371 (67.70%), respectively, according to the 2014 guidelines. However, according to the 2019 guidelines, 10 cases (1.82%) were reclassified as IHC 1+, 2 cases in the group 2 were reclassified as negative, and all the originally equivocal cases in group 4 were reclassified as negative. Finally, the total number of positive and negative cases for HER2 were 94 (17.15%) and 454 (82.85%), respectively.Conclusions:After applying the 2019 guidelines, the number of IHC 2+ cases decreases, and the positive rate for HER2 also decreases slightly due to the reevaluation change in groups 2 and 4, leading to reclassification of the cases that were deemed equivocal according to the 2014 guidelines. In general, the new 2019 guidelines are more reasonable and easier to use.