Background Breast cancer (BC) remains the leading cause of cancer‐related deaths worldwide. High recurrence risk Luminal BC receives adjuvant chemotherapy in addition to standard hormone therapy. Considering the heterogeneity of Luminal B BC, a more accurate classification model is urgently needed. Methods In this study, we retrospectively reviewed the data of 1603 patients who were diagnosed with HER2‐negative breast invasive ductal carcinoma. According to the expression level of PR and Ki‐67 index, the Luminal B (HER2‐negative) BCs were divided into three groups: ER+PR−Ki67 low (ER‐positive, PR‐negative, and Ki‐67 index <20%), ER+PR+Ki67 high (ER‐positive, PR‐positive, and Ki‐67 index ≥20%), and ER+PR−Ki67 high (ER‐positive, PR‐negative, and Ki‐67 index ≥20%). The cox proportional hazards regression model was used to evaluate the correlation between each variable and outcomes. Besides, discriminatory accuracy of the models was compared using the area under the receiver operating characteristic curve and log‐rank χ 2 value. Results The analysis results showed that there was a significant correlation between subtypes using this newly defined classification and overall survival ( p < 0.001) and disease‐free survival (DFS) ( p < 0.001). Interestingly, patients in the ER+PR−Ki67 high subgroup have the worst survival outcome in Luminal B (HER2‐negative) subtype, similar to Triple‐negative patients. Besides, the ER+PR+Ki67 high has worse 5‐year DFS compared with Luminal A group. There was a significant relationship between the regrouping subtype and the recurrence score index (RI) ( p < 0.001). Moreover, the results showed that patients in ER+PR–Ki67 high subtype were more likely to have high RI for distance recurrence (RI‐DR) and local recurrence (RI‐LRR). Our newly defined classification has a better discrimination ability to predict survival outcome and recurrence score of Luminal B (HER2‐negative) BC patients, which may help in clinical decision‐making for individual treatment.

Background Neoadjuvant chemotherapy with dual-targeted therapy is the standard treatment for human epidermal growth factor 2 (HER2)-positive breast cancer. Although the dual-targeted therapy has significantly improved the pathological complete response (pCR) rate, further investigation is needed to identify biomarkers that predict the response to neoadjuvant therapy. Methods This retrospective study analyzed 353 patients with HER2-positive breast invasive ductal carcinoma. The correlation between clinicopathological factors and pCR rate was evaluated. A nomogram was constructed based on the results of the multivariate logistic regression analysis to predict the probability of pCR. Results The breast pCR (b-pCR) rate was 56.1% (198/353) and the total pCR (t-pCR) rate was 52.7% (186/353). Multivariate analysis identified ER status, PR status, HER2 status, Ki-67 index, and neoadjuvant chemotherapy regimens as independent indicators for both b-pCR and t-pCR. The nomogram had an area under the receiver operating characteristic curve (AUC) of 0.73 (95% CI: 0.68–0.78). According to the nomogram, the t- pCR rate was highest in the ER-PR- HER2-positive patients (131/208) and lowest in the ER + PR + HER2-positive patients (19/73). The subgroup analyses showed that there was no significant difference in pCR rate among the neoadjuvant chemotherapy regimens in ER positive, PR positive, HER2 IHC 2+, Ki67 index < 30% population. However, for ER-PR-HER2-positive patients, the neoadjuvant chemotherapy regimen has a great influence on the pCR rates. Conclusions Patients with ER-negative, PR-negative, HER2 3 + and high KI-67 index were more likely to achieve pCR. THP may be used as an alternative to AC-THP or TCbHP in selected HER2-positive patients.