In a study of primary invasive HER2+ breast cancer, the presence of CD32B positive CLSs at the breast cancer-adipose tissue margin was associated with a BMI >25 kg/m2 and shorter time to metastatic disease in trastuzumab-treated patients (HR 4.2, 95% CI, 1.01–17.4). This evidence concerns the gene ERBB2 and breast cancer.