5. Patients with multiple foci of invasive cancer in the same breast are eligible if any single lesion meets the above size criteria and all sampled lesions are histologically similar and HER2+ (whether radiographically detected lesions separate from the target lesion are sampled for histologic evaluation is left to the discretion of the treating physicians). The presence of DCIS or LCIS in either breast will not render a patient ineligible. Patients with a small focus of invasive cancer detected in the contralateral breast (clinical T1a/bN0) are eligible, whether the contralateral tumor in HER2+ or HER2-, while patients with a more advanced cancer in the contralateral breast are not eligible; in patients with a small focus of invasive cancer in the contralateral breast only the histologic response in the breast containing the target lesion will be considered in determining the patient's pathologic response.