Cancer is predominantly a disease of aging, and older adults with cancer represent the majority of cancer diagnoses and deaths in the United States. Despite dramatically increasing numbers of older adults developing cancer, our understanding of this potentially vulnerable population remains limited. We are ill prepared to care for this surging demographic, and the translation of scientific discoveries arising in the lab or clinical research into clinical applications to care for the aging population has never been more important. This chapter will focus on proposed biomarkers of functional age that could complement existing assessments of older adults with cancer. First, we will discuss biological markers of aging such as systemic inflammatory markers and markers of senescence. Second, we will review the role of body composition and imaging for evaluating sarcopenia. Next, we focus on cardiovascular performance and discuss the potential importance of gauging exercise capacity. Lastly, we address potential methodologic challenges and design considerations related to translational research in older adults with cancer. Translational research offers several novel avenues to improve our assessments of older patients to aid in the assessment of the risks and benefits of treatments. Further development of these promising areas is necessary to improve the quality of care for this growing and vulnerable population.