目的:研究人乳腺癌表皮生长因子受体2(human epithelial growth factor receptor-2, HER2)低表达的病理特征,通过RT-qPCR检测HER2的表达水平,追踪从穿刺活检到接受新辅助化疗后HER2表达的演变,探索其新辅助化疗的疗效。方法:选取2019年1月-2022年12月包头市肿瘤医院收治的293例浸润性乳腺癌患者(HER2阴性型134例,HER2低表达型159例),分别应用FISH及RT-qPCR检测两组患者HER2表达水平。结果:与HER2阴性组相比,HER2低表达组在雌激素受体(estrogen receptor, ER)、孕激素受体(progesterone receptor, PR)、Miller-Payne(MP)分级、P53及淋巴结转移差异具有统计学意义(P＜0.05);与年龄(P=0.731)差异无统计学意义;FISH检测结果显示两组数据显著重叠;RT-qPCR检测mRNA表达量,两组差异具有统计学意义(P＜0.001);采用ROC曲线明确最佳阈值为184.18;RT-qPCR与IHC相比,两种检测方法的一致性为0.502,属中等水平;新辅助化疗前后,HER2不一致的发生率为39.8%;HER2状态与获得pCR的概率之间存在密切相关(P=0.005)。结论:乳腺癌HER2低表达与阴性的病理特征不同。RT-qPCR检测HER2 mRNA的表达量可作为IHC检测HER2低表达的补充技术。HER2的表达在新辅助治疗后表现出高度不稳定性。此外,HER2低表达乳腺癌患者的新辅助化疗的疗效较差。
Objective: To study the pathological characteristics of low HER2 expression in human breast cancer, detect the expression level by RT-qPCR, track the evolution of HER2 expression from needle biopsy to receive neoadjuvant treatment, and explore the efficacy of neoadjuvant chemotherapy. Methods: A total of 293 HER2 negative patients and low HER2 expression admitted to Baotou Cancer Hospital from January 2019 to December 2022 were selected .FISH and RT-qPCR were used to detect the expression level of HER2 in the two groups. Results: In contrast to the HER2 negative group, low expression group of HER2 was significant statistical differences in ER, PR, MP grade, P53 and lymph node metastasis (P＜0.05); There was no obvious relationship with age (P=0.731); The results of FISH analysis showed that the data of the two groups were significantly overlapped; and the mRNA expression level of RT-qPCR was a statistical difference (P＜0.001).The optimal threshold by ROC curve was 184.18. RT-qPCR compared to IHC, the consistency between the two methods was 0.502, a medium level. Before and after neoadjuvant chemotherapy, the incidence of HER2 discordance was 39.8%; There is a close correlation between HER2 status and the probability of obtaining pCR (P=0.005). Conclusion: HER2 low breast cancer differ from HER2 negative in pathological features. Quantitative detection of HER2 mRNA expression by RT-qPCR can be used as a complementary technique for IHC method. The expression of HER2 showed high instability following neoadjuvant therapy. Moreover, neoadjuvant chemotherapy has less efficacy in patients with HER2 low breast cancer.
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