ERBB2 and colonic neoplasm: Breast cancer (35)January 2019: dx with stage 1a ER+/PR+/HER2+ IDC, treated with trastuzumab initially then mastectomy while undergoing surgery for colon cancer, then continued trastuzumab and tamoxifenOctober 2019: tamoxifen and trastuzumab stopped due to the aggressive nature of colon cancer