Abstract: Objective:To investigate the differences in the curative effects of neoadjuvant chemotherapy (NAC) for different subtypes of Luminal B breast cancer and its prognosis, and to discuss the clinical treatment characteristics of different subgroups. Methods: A total of 246 cases of Luminal B like breast cancer patients who completed the projected NAC courses and surgical treatment were selected. All the biopsy specimens before treatment were positive for estrogen receptot(ER). According to the expressions of progesterone receptor(PR), human epidermal growth factor-2(Her-2) and cell proliferation nuclear antigen Ki-67, 246 cases of Luminal B breast cancer patients were divided into 3 subgroups. A subgroup (PR low expression group), Her-2 negative and PR< 20% or negative, Ki-67 any levels; B subgroup (PR high expression group), Her-2 negative, PR ≥ 20% and Ki-67 ≥ 14%; C subgroup (Her-2 positive group), Her-2 positive, Ki-67 and PR any levels. The clinical pathological materials and follow-up recurrence events of the patients were collected. Results: Among the three subtypes of Luminal B breast cancer, there were no significant differences in the age, the size of primary tumor and the stage of TNM (P>0.05). There were significant differences in the lymph node metastasis rate among three subgroups (P=0.018), and the lymph node metastasis rate was the highest in A subgroup among three subgroups. There were no significant differences in the clinical response and pathological response among three subgroups (P=0.123, P=0.06). 8.5% (21/246) patients achieved the pathological complete response (pCR); the rates of pCR in three subgroups had statistically significant difference (P=0.009); the rate of pCR in C subgroup was the highest, and the rate of pCR in B subgroup was the lowest. The Log-Rank test of the survival curves of three subgroups had not statistically significant difference (P=0.216), but the 3-year disease-free survival(DFS) and 5-year DFS of the patients in B subgroup were slightly higher than those in other two groups. The DFS of the patients in C subgroup was longer than that of the patients with Her-2 overexpression breast cancer at the same period, and the difference was statistically significant (P=0.047). Conclusion: Her-2 positive Luminal B breast cancer is more likely to achieve pCR in NAC and the prognosis is better than Her-2 overexpressing breast cancer. The patients with high expression of PR in Luminal B breast cancer patients have a tend of overall survival advantage compared with the patients with PR low expression and Her-2 positive expression.

Key words: neoadjuvant chemotherapy, breast neoplasms, prognosis analysis, Luminal B