HER2-low tumors have shown promise in response to antibody–drug conjugates (ADCs) in recent clinical trials, underscoring the need to characterize this group’s clinical phenotype. In this study, we aimed to explore the clinicopathological features, survival rates, and HER2 amplicon mRNA expression of women affected with HER2-low breast cancer, compared with HER2-negative and HER2-positive groups. We included 516 breast cancer patients from Colombia, for whom we compared clinicopathological features, mRNA expression of three HER2 amplicon genes (ERBB2, GRB7andMIEN1), survival and risk of mortality between HER2-low cases (1+ or 2+ with negative in situ hybridization (ISH) result) with HER2-positive (3+ or 2+ with positive ISH test) and HER2-negative (0+) cases. A higher proportion of patients with better-differentiated tumors and a lower proliferation index were observed for HER2-low tumors compared to the HER2-positive group. Additionally, HER2-low tumors showed higher mRNA expression of theERBB2gene and longer overall survival rates compared to HER2-negative cases. Nonetheless, a Cox-adjusted model by ER status and clinical stage showed no statistically significant differences between these groups. Our results show differences in important clinicopathological features between HER2-low and both HER2-positive and negative tumors. Given this unique phenotype, it is crucial to evaluate the potential advantages of ADC therapies for this emerging subtype of breast cancer.
近期临床试验表明，HER2低表达肿瘤对抗体药物偶联物（ADCs）治疗具有良好反应，这凸显了明确该亚型临床表型特征的必要性。本研究旨在比较HER2低表达、HER2阴性及HER2阳性三组乳腺癌患者的临床病理特征、生存率及HER2扩增子mRNA表达差异。我们纳入516例哥伦比亚乳腺癌患者，将HER2低表达病例（免疫组化1+或2+且原位杂交阴性）分别与HER2阳性病例（免疫组化3+或2+且原位杂交阳性）及HER2阴性病例（免疫组化0+）进行对比，分析其临床病理特征、三种HER2扩增子基因（ERBB2、GRB7和MIEN1）的mRNA表达水平、生存率及死亡风险。结果显示：与HER2阳性组相比，HER2低表达组中肿瘤分化程度更高、增殖指数较低的患者比例显著增加；与HER2阴性组相比，HER2低表达组ERBB2基因mRNA表达水平更高，总生存期更长。然而，经雌激素受体状态和临床分期校正的Cox模型显示，这些组间差异无统计学意义。我们的研究揭示了HER2低表达肿瘤与HER2阳性及阴性肿瘤在关键临床病理特征上的差异。鉴于其独特的表型特征，评估ADC疗法对这一新兴乳腺癌亚型的潜在治疗优势至关重要。
Characterization of HER2-Low Breast Tumors among a Cohort of Colombian Women
肿瘤(癌症)患者之家