CI-994 is primarily investigated for its potential in cancer treatment, particularly as a histone deacetylase (HDAC) inhibitor. It works by modifying gene expression, which can lead to the suppression of tumor growth and the induction of cancer cell death. Clinical studies have explored its use in combination with other chemotherapeutic agents to enhance their efficacy, especially in treating solid tumors and hematologic malignancies. Additionally, CI-994 has been studied for its role in improving the sensitivity of cancer cells to radiation therapy, making it a promising candidate for multimodal cancer treatment strategies.