The comparative analysis of HER2 positive and negative breast tumors within the two groups of obese and non-obese patients shows a higher preponderance of the histological subtype HER2 positive for immunohistochemistry in obese patients, p-value=0.6825, Difference (CI95%)=0.08 (-0.16 to 0.32). There are no statistically significant differences between obese and non-obese patients (p > 0.05). The gene discussed is ERBB2; the disease is breast neoplasm.