ERBB2 and breast cancer: Since the colon cancer was more advanced it was treated firstSince the breast cancer was HER2+ and hormone receptor positive, HER2 and hormonal therapy were added to the colon cancer chemotherapy regimenWhen surgery was done for the colon cancer, concurrent mastectomy was performedSince the breast cancer had low risk for recurrence, hormonal therapy and trastuzumab were stopped when colon cancer was progressing and life limiting