CI-994 is primarily investigated for its potential as an anticancer agent, specifically due to its ability to inhibit histone deacetylases (HDACs). By modulating gene expression through epigenetic mechanisms, it promotes cell cycle arrest and induces differentiation or apoptosis in tumor cells. It has been studied in clinical trials for various solid tumors, including breast, lung, and colorectal cancers, often in combination with other chemotherapeutic agents to enhance efficacy. Its oral bioavailability makes it a favorable candidate for outpatient treatment regimens. Research also explores its role in overcoming drug resistance, potentially improving outcomes in refractory cancers.