Ki-67 index and galectin-3 as surrogate markers for predicting disease-free survival in luminal-type breast carcinoma treated with neoadjuvant chemotherapy

Background: Residual cancer burden (RCB) is an important marker for patients with breast carcinoma treated with neoadjuvant chemotherapy (NACT). However, the association between RCB and prognosis is relatively less significant in residual luminal-type breast carcinoma (LTBC). Associations between clinicopathological variables, including RCB class, and immunohistochemical (IHC) markers with disease-free survival (DFS) were analyzed. Methods: Expression of Ki-67, calreticulin, clusterin, galectin-3, mucin-1, and p27 was assessed in tissue microarray slides of 55 post-NACT resection specimens from LTBC patients treated with docetaxel and doxorubicin. Patients' age, pre-NACT progesterone receptor status, lymphovascular invasion, histologic grade, ypT category, ypN category, RCB class, and IHC markers were analyzed for their association with DFS using Kaplan-Meier analysis and Cox proportional hazards models. Results: Twenty of the 55 patients developed recurrence or distant metastasis. A Ki-67 index > 2.7% and high galectin-3 expression were associated with shorter DFS on Kaplan-Meier analysis (p < .001 and p = .018, respectively). Other clinicopathological and IHC markers were not significantly associated with DFS. In the multivariate Cox proportional hazards model, a Ki-67 index > 2.7% (hazard ratio, 7.23; p < .001) and high galectin-3 expression (hazard ratio, 4.51; p = .007) remained independent predictors of shorter DFS. Conclusions: The Ki-67 index and high galectin-3 expression in post-NACT resection specimens may serve as surrogate markers for predicting recurrence in LTBC.