Elevated Soluble Galectin-3 as a Marker of Chemotherapy Efficacy in Breast Cancer Patients: A Prospective Study

Purpose Galectin-3 (Gal-3) is a glycan-binding lectin with a debated role in cancer progression due to its various functions and patterns of expression. The current study investigates the relationship between breast cancer prognosis and secreted Gal-3. Methods Breast cancer patients with first time cancer diagnosis and no prior treatment (n=88) were placed in either adjuvant or neoadjuvant setting based on their treatment modality. Stromal and plasma Gal-3 levels were measured in each patient at the time of diagnosis and then throughout treatment using immunohistochemistry (IHC) and ELISA respectively. Healthy women (>18 years of age, n=63) were used to establish baseline levels of plasma Gal-3. Patients were followed for 84 months for disease free survival analysis. Results Enhanced levels of plasma (adjuvant) and stromal (neo-adjuvant) Gal-3 were found to be markers of chemotherapy efficacy. The patients with chemotherapy induced increase in extracellular Gal-3 had longer disease-free interval and significantly lower rate of recurrence during 84-month follow-up compared to patients with unchanged or decreased secretion. Conclusion The findings support the use of plasma Gal-3 as a marker for chemotherapy efficacy when no residual tumor is visible through imaging. Furthermore, stromal levels in any remaining tumors post chemotherapy can also be used to predict long term prognosis in patients. Key points Increased Gal-3 secretion due to chemotherapy leads to better prognosis and longer disease-free survival. The analysis of soluble Gal-3 expression could be useful as a support tool in predicting treatment efficacy in patients with no visible tumor remaining for follow up through imaging.