L-778123 hydrochloride is primarily used in research settings to study its potential as an inhibitor of farnesyltransferase, an enzyme involved in the post-translational modification of proteins. This compound is of particular interest in cancer research, as inhibiting farnesyltransferase can disrupt the signaling pathways that promote tumor growth and survival. It has been investigated for its potential to inhibit the proliferation of cancer cells, especially in cancers driven by Ras mutations. Additionally, it serves as a tool in biochemical studies to better understand the role of protein prenylation in cellular processes. Its application extends to exploring combination therapies, where it may enhance the efficacy of other anticancer agents.