Galectin-1 Expression in Breast Cancer Stroma: Prognostic Value in Triple-Negative Breast Cancer

Galectin-1 is a lectin with immunosuppressive effect in different solid tumors. We investigated galectin-1 expression in triple-negative breast cancer (TNBC) to determine its prognostic value.

We examined 95 TNBC surgical samples in tissue microarrays with galectin-1 immunohistochemistry (intensity and percentage of staining) and looked for influences on overall and progression-free survivals (PFSs) with the help of Kaplan-Meier estimates. Univariable and multivariable Cox regressions were also analyzed.

According to Kaplan-Meier curves, a significantly worse overall survival (OS) was found for TNBC patients showing intense or ≥50% galectin-1 stromal interface staining versus those lacking it. Cox regression analyses suggested that galectin-1 expression was an independent prognosticator in TNBC. According to the quantity of stromal tumor-infiltrating lymphocytes (sTILs), significant survival differences depending on galectin-1 status were only seen in the low sTILs (<30%) subset. Multivariable analysis suggested that galectin-1 expression was an independent prognosticator for PFS.

The immunosuppressive effects of galectin-1 forming a shield around tumor nests may form an immune escape mechanism and can explain the worse OS and PFS we found in TNBC. Owing to the exploratory nature of the study, the results need confirmation in order to investigate the potentials of anti-galectin-1 therapies.