Department of Breast and Endocrine Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
Tokai J Exp Clin Med. 2020 Dec 20;45(4):176-181.
Trastuzumab may convert human epidermal growth factor receptor-2 (HER2)-positive primary breast tumors to HER2-negative tumors after chemotherapy. This study determined whether trastuzumab increases the number of patients with conversion to HER2-negative status and assessed the effect of neoadjuvant chemotherapy.
We retrospectively reviewed 46 patients diagnosed with HER2-overexpression in primary breast cancers at Tokai University Hospital, receiving neoadjuvant chemotherapy by immunohistochemistry and fluorescence in situ hybridization (FISH). Surgical specimens of patients achieving less than pathological complete response (pCR) were verified for sufficient residual tissue to evaluate post-treatment HER2 status by dual-color in situ hybridization (DISH).
pCR was achieved in 8 of the 46 (17.4%) patients. The residual tumor was sufficient for a ssessing post-treatment HER2 status in 25 patients. DISH of pretreatment specimens confirmed HER2 amplification prior to therapy. Of the 25 HER2-positive patients, DISH revealed 3 were HER2 negative in pretreatment specimens. No post-treatment tumors were HER2-negative according to DISH in HER2-positive pre-treatment tumors. Among HER2-negative pretreatment tumors, 1 post-treatment tumor was HER2 positive and 2 had stable HER2 status.
HER2 status determined by DISH was stable between pretreatment breast tumors and residual tumors. However, a small discrepancy regarding HER2 status determined by immunohistochemistry and DISH existed.
曲妥珠单抗（Trastuzumab）可能会使化疗后的人表皮生长因子受体 2（HER2）阳性原发性乳腺癌转化为 HER2 阴性肿瘤。本研究旨在确定曲妥珠单抗是否会增加 HER2 阴性转化患者的数量，并评估新辅助化疗的效果。
我们回顾性分析了在东海大学医院就诊的 46 例 HER2 过表达的原发性乳腺癌患者，通过免疫组织化学和荧光原位杂交（FISH）接受新辅助化疗。对于未达到病理完全缓解（pCR）的患者，我们对手术标本进行了评估，以确定是否有足够的残留组织进行双染原位杂交（DISH）以评估治疗后 HER2 状态。
46 例患者中，8 例（17.4%）达到 pCR。25 例患者的残留肿瘤组织足够评估治疗后 HER2 状态。DISH 检测治疗前标本证实了治疗前 HER2 扩增。在 25 例 HER2 阳性患者中，DISH 显示 3 例治疗前标本 HER2 阴性。在治疗前 HER2 阳性肿瘤中，DISH 未发现任何治疗后肿瘤 HER2 阴性。在治疗前 HER2 阴性肿瘤中，1 例治疗后肿瘤 HER2 阳性，2 例 HER2 状态稳定。
DISH 检测的 HER2 状态在治疗前和残留肿瘤之间是稳定的。然而，免疫组织化学和 DISH 检测的 HER2 状态之间存在小的差异。
