[Clinicopathological features and prognosis of breast cancer with human epidermal growth factor receptor 2 low expression].

objectiveThere is an increasing interest in human epidermal growth factor receptor 2 (HER2) low expression breast cancer with the result of novel anti-HER2 antibody-drug conjugates for breast cancer. HER2 low expression breast cancer is expected to become a new type of breast cancer. This study analyzed and compared the clinicopathological features and survival data of breast cancer with HER2 low expression group [immunohistochemistry (IHC) 1+ or IHC 2+, and fluorescence

methodsAmong 1 250 female patients with primary non-metastatic breast cancer admitted to the Breast Disease Center of Peking University First Hospital from January 2014 to December 2017, 969 cases were HER2 negative (IHC 0, 1+, 2+, and FISH was not amplified). The clinicopathologic features and prognosis of the patients with HER2 low expression (IHC 1+ or 2+, and unamplified by FISH) and HER2 zero expression (IHC 0) were analyzed. Disease free survival (DFS) and overall survival (OS) were evaluated, survival rates were calculated by Kaplan-Meier curve, and survival differences were compared by Log-rank test. Cox regression analysis of univariate and multivariate prognostic factors. Bilateral test was used, and

resultsIn the 969 patients with HER2 negative breast cancer, 606 had HER2 low expression (62.54%) and 363 had HER2 zero expression (37.46%). Compared with breast cancer with HER2 zero expression, those with HER2 low expression had higher N stage (

conclusionHER2 low expression breast cancer accounts for about half of all breast cancers, and the incidence is much higher than that of HER2 positive breast cancer. Its clinicopathologic features are heterogeneous, and the status of hormone receptor expression has an impact on the clinical biology of this group.