The results from the meta-analysis conducted by Lohmann AE et al. [30] show that, in comparison to non-obese women, obesity at the time of BC diagnosis negatively affects the disease-free survival period (DFS) in all BC subtypes, being worse for HR + HER2- cases (HR = 1.26; 95% CI: 1.13 to 1.41), and it significantly reduces the overall survival (OS) of patients exhibiting cancer subtypes HR + HER2- (HR = 1.39, 95% CI: 1.20 to 1.62), HER2+ (HR = 1.18; 95% CI: 1.05 to 1.33), and TNBC (HR = 1.32; 95% CI: 1.13 to 1.53). This evidence concerns the gene ERBB2 and Obesity.