PGR and breast cancer: While multivariate analysis showed no significant correlations (including Ki-67 expression), the univariate analysis (Table 3) indicated that in GD2 positive specimens the possibility of being TNBC was significantly higher than being ER/PR +/HER2– (OR = 3.26; p = 0.04; 95% CI [1.03–10.37]), suggesting how GD2 may represent a novel marker capable to identify a still elusive BC subtype.