The results of a Phase II trial recently testing lapatinib for the treatment of HER2-positive breast cancer (early-stage invasive breast cancer and DCIS) showed that lapatinib (at 1,500 mg/day) decreased breast cancer cell proliferation in ER-negative tumors and in DCIS and ductal hyperplasia lesions (26). Here, ERBB2 is linked to invasive breast carcinoma.