THZ1 2HCl is primarily used in research settings to study its effects on cancer cells. It functions as a potent inhibitor of CDK7, a cyclin-dependent kinase involved in cell cycle regulation and transcription. By inhibiting CDK7, THZ1 2HCl disrupts the growth and survival of cancer cells, making it a valuable tool in understanding cancer biology and developing potential therapeutic strategies. It is particularly studied in the context of various cancers, including triple-negative breast cancer, small cell lung cancer, and T-cell acute lymphoblastic leukemia. Researchers also explore its role in combination therapies to enhance the efficacy of existing cancer treatments. Its application extends to preclinical studies aimed at identifying new drug targets and understanding the molecular mechanisms underlying cancer progression.