Poster Presentation 2025 Joint Meeting of the COSA ASM and IPOS Congress

Large Chinese Cohort Validates 70-Gene Signature (MammaPrint) for Breast Cancer Risk Stratification (n=1900) (126226)

Hong Liu 1 , Nanlin Li 2 , Yuan Sheng 3 , Hong Hu 4 , Cheng Wang 5 , Wenbin Zhou 6 , Guohua Liu 7
  1. Tianjin Cancer Hospital, Airport Hospital, Tian jin, China
  2. The First Affiliated Hospital of Air Force Medical University, Xijing Hospital, Xi'an, Shaanxi, China
  3. Shanghai Changhai Hospital, The First Affiliated Hospital of Naval Medical University, shanghai, China
  4. Shenzhen People's Hospital, Department of Oncology, Shenzhen, China
  5. Shanghai Second People's Hospital, Department of Oncology, Shanghai, China
  6. Jiangsu Province Hospital, Department of Oncology, Nanjing, Jiangsu, China
  7. Anyang Tumor Hospital, Department of Oncology, Anyang, Henan, China

Background: Genomic risk stratification using the 70-gene signature (MammaPrint, MP) is established in Western cohorts but lacks large-scale validation in Chinese patients with early 

stage breast cancer (BC). This study aimed to bridge this gap.

Methods: We performed MP testing on tumor samples from 1900 consecutive patients with estrogen receptor-positive (ER+), HER2-negative (HER2-) early stage BC treated. 

Associations between MP risk classification and clinicopathological features were analyzed.

Results: MP classified 41.1% of patients as High Risk. MP-High Risk status was significantly associated with higher histological grade, Ki67 index >14%, and lower progesterone receptor (PR) 

expression (all p<0.05). Crucially, the proportion of patients exhibiting clinical high-risk/genomic low-risk discordance (defined by clinical parameters vs. MP) was 24% in this Chinese cohort, 

closely aligning with the 23% rate observed in the landmark MINDACT trial.

Practice Impact: This validation confirms MP's utility in refining risk stratification within the Chinese population, providing critical genomic information to guide personalized adjuvant therapy decisions and potentially spare low-genomic-risk patients from overtreatment.

Discussion: This represents the first large-scale validation of the MammaPrint assay in a Chinese BC cohort, successfully filling a critical data gap and supporting its clinical applicability for 

precision oncology in this population.