Andrew Koff, PhD, is an Emeritus Member of the Sloan Kettering Institute. From 1993-2026 he was a Member of the Molecular Biology Program. He is an internationally recognized molecular biologist known for his foundational work understanding the regulation of cell proliferation and cellular quiescence. His work has been central to defining conserved molecular pathways that govern the decision of cells to continue cycling or to exit the cell cycle into a durable non-proliferative state, a fundamental biological choice with broad implications for development, cancer biology and therapeutic response.
His research helped clarify two critical biological decisions. First, his early work identified conserved proteins, particularly regulators of cyclin-dependent kinases (CDKs), that control whether a cell continues through the mitotic cycle or exits into a non-dividing state. This decision point is central to development and tissue maintenance, and its inappropriate regulation is a major contributor to cancer. Second, he also uncovered regulatory networks that drive cells that have exited the cycle into a stable senescent state in response to pharmacological inhibition of CDK4. This regulatory circuit, called geroconversion, is partly responsible for how patients with dedifferentiated liposarcoma respond to CDK4 inhibition therapies. These two decisions – whether to divide and whether to stay stopped – are deeply conserved across biology and highly relevant to cancer therapy. By linking CDK4 inhibition induced cellular senescence in a clinical context, Koff’s work helped shift the perspective of these drugs from purely cytostatic agents to modulators of long-term cell fate, opening new avenues for combination therapies and biomarker-driven treatment strategies across multiple cancers.
His career has been marked not only by influential scientific discoveries but also by sustained leadership, service, and mentorship across the biomedical community. He received prestigious fellowships from the Pew Charitable Trusts and the Sarcoma Foundation of America, reflecting the impact of his work in cell cycle regulation and its pharmacological control in cancer therapy. In 2006, the Institute for Scientific Information recognized him as one of the most highly cited researchers in molecular biology and genetics, an indicator of how widely his research has shaped the field. Beyond his own laboratory, Dr. Koff played an active role in guiding research and innovation. He served on scientific advisory boards for pharmaceutical and biotechnology companies, as well as on steering committees for international scientific organizations. His expertise was also sought in peer review and funding decisions, including service on panels for the National Institutes of Health, the National Cancer Institute, The Austrian Marshall Plan Foundation, and the American Cancer Society, along with other international agencies and editorial boards. Equally significant has been his contribution to education and mentorship of graduate students and post-doctoral fellows. During his tenure at Memorial Sloan Kettering Cancer Center, he was deeply involved in training the next generation of scientists. He contributed to the longstanding educational alliance with Weill Cornell Medical College, played a role in the early curriculum development and advising structure of the Gerstner Sloan Kettering Graduate School of Biomedical Sciences, and in the partnership program with City College of New York.
Taken together, these contributions underscore a career that has shaped not only our understanding of cell cycle control and cancer therapy, but also the broader scientific ecosystem through leadership, service, and education.