BACKGROUND: Traditionally, breast cancer HER2 status was categorized simply as positive or negative, with a preference for the negative designation due to its more favorable implications. However, recent advancements in classification have introduced a HER2 low status (score 1+ and 2+ without amplification), which is now recognized in a significant proportion of breast cancer cases. This newly identified HER2 low status is currently under investigation for its potential as a positive prognostic marker, particularly in the context of antibody-drug conjugate therapies. This study offers an overview of the novel HER2 classification as applied to our center's patients, providing insights into prognostic factors and outcomes. METHODS: The study analyzed breast cancer patients managed at the university teaching hospital of Tours between 2000 and 2013. Tumors were reclassified according to the new histological classification including the Her2-low status. RESULTS: Our patient cohort was distributed into three distinct groups: HER2-low (37%), HER2-negative (57%) and HER2-positive (11%). Notably, HER2-positive patients were on average younger (56.5 years) than those in the other groups, who averaged 60 and 61 years, respectively (p=0.003). No significant disparities emerged concerning BMI, recurrence patterns (locoregional or distant), or time to recurrence across these groups. However, differences were observed in terms of tumor phenotype, with luminal A tumors being more prevalent in the HER2 low and negative groups, while the luminal B subtype was predominant in the HER2 positive group. Furthermore, HER2-positive patients exhibited a higher prevalence of negative hormone receptors (43%), contrasting with 8% in the HER2-low group and 15% in the HER2-negative group. CONCLUSION: Our study highlights differences in age and hormonal receptor status among HER2 status groups. The introduction of HER2-low classification opens the door to new treatment strategies, especially with antibody-drug combinations that use HER2 receptors to deliver drugs. Although significant differences in survival rates were not found, ongoing research is crucial to understand how this new classification affects patient parameters. Additionally, it is essential to consider individual factors like age and hormone receptor status when deciding on the best treatment approach.