Additional Study Information: The purpose of this study is to find the best dose and effects of BBO-10203 when used alone or in combination with Trastuzumab in HER2-positive advanced breast cancer (aBC) or HR-positive, HER2-negative aBC or advanced non-small cell lung cancer (aNSCLC) with a KRAS (Kirsten rat sarcoma) mutation or advanced colorectal cancer (aCRC) with a KRAS mutation. BBO-10203 has not been approved by the Food and Drug Administration (FDA). Trastuzumab is FDA approved but not in combination with BBO-10203. This is a first in human study.