A Study of Oral MBQ-167 in Participants With Advanced Breast Cancer

The main questions this clinical trial aims to answer are: * What, if any, are the side effects of different dose levels in humans? * What is the maximum tolerated dose? * How does the human body process the drug? * Does the drug slow, stop or eliminate cancer in human participants? Participants will be asked to: * provide informed consent * be evaluated by physicians and provide laboratory specimens to determine if eligible * take MBQ-167 orally twice a day for at least 21 days * may continue dosing, if safe to do so, until not effective or other decision to stop is made * participate in multiple visits that include additional evaluations, laboratory tests and diary review until after stopping the investigational drug