MCL1 and neoplasm: In SCLC and some pulmonary carcinoid tumors, a combination of chemotherapy agents, specifically those that down regulate Mcl-1, and Navitoclax, a drug that inhibits anti-apoptotic Bcl proteins, has had some success decreasing tumor size; patients who received the combination treatment for longer than one year displayed a 22% - 35% decrease in tumor size [87].