Ganglioside GD2 Expression Is Associated With Unfavorable Prognosis in Early Triple-negative Breast Cancer.

Background/aim: Gangliosides (acidic glycosphingolipids) have crucial regulatory roles in normal physiological processes, as well as in pathological conditions, including tumor onset and progression. GD2 is highly expressed in triple-negative breast cancer (TNBC), particularly in cancer stem cells. However, little is known on the clinical impact of GD2 expression on the prognosis of TNBC. Consequently, we aimed to investigate the association between GD2 expression in TNBC and the prognosis of TNBC.

Patients And Methods: We assessed GD2 expression in 76 patients with primary TNBC who had undergone surgery at our Institute between 2012 and 2015 using immunohistochemical analysis with a tissue microarray technique. We investigated the relationship between GD2 expression and clinicopathological factors in TNBC, recurrence-free survival (RFS), and overall survival (OS).

Results: Increased GD2 expression was observed in 45% of TNBC patients. There was no significant association between GD2 expression and clinicopathological factors in TNBC. The 5-year RFS rate among patients with GD2-positive TNBCs was significantly worse than that among patients with GD2-negative TNBCs (75.4% and 94.9%; HR=4.931; 95%CI=1.024-23.752; p=0.027). The OS in patients with GD2-positive TNBCs tended to be inferior to that of patients with GD2-negative TNBCs (HR=5.357; 95%CI=0.599-47.939; p=0.092). Interestingly, in patients with GD2-positive TNBCs, a higher grade of tumor-infiltrating lymphocytes (TILs) displayed a significantly better impact on OS (TILs-high vs. TILs-low; p=0.04). Both univariate and multivariate analyses showed that GD2 expression negatively affected RFS (p=0.027, p=0.021, respectively).

Conclusion: GD2 expression is an independent unfavorable prognostic factor for TNBC.