The Biology of AYA Cancers

Investigating the potential biological basis of age-related differences in outcome for AYA with cancer could lead to a better understanding of the biology, facilitate the development of new diagnostic and predictive markers, and identify novel therapeutic targets and treatment approaches for AYA patients. The evidence that cancers in AYA patients may differ biologically from those in older and younger populations includes data from numerous laboratories. However, much of this evidence is preliminary, and large comprehensive studies to confirm and validate these findings are only now beginning to get underway. Indeed, there may be substantial differences in biological and molecular features between different age groups even within the population of AYA patients with a specific cancer type. If age is a good surrogate for a unique tumor biology associated with AYA cancers, then studies of cancers in AYA patients will almost certainly illuminate alternative tumorigenic pathways and will also likely benefit patients in other age groups whose tumors exhibit similar biological/molecular features. The biologic, molecular, and clinical features of five AYA cancers (colon, breast, acute lymphoblastic leukemia, melanoma, and sarcoma) are highlighted in this chapter, and the current state of research for each of them is examined. What will be required to better diagnose, treat, and predict response in patients with AYA cancer is also discussed.