Characterizing Osteosarcoma Through PTEN and PI3K: What p53 and Rb1 Can’t Tell Us

Attention has been given to the fact that overall survival of osteosarcoma has plateaued over the last 30 years despite the addition of chemotherapy regimens. Elucidating the involvement of p53 and Rb1 in osteosarcoma has not yielded many novel treatments, but recent studies have started to characterize how the PTEN and the PI3K pathway can contribute to osteosarcoma. PTEN is a tumor suppressor that regulates a variety of signal transduction pathways and cellular processes, mainly by antagonizing PI3K activity and shutting down the PI3K/Akt pathway. Loss of PTEN function with concurrent PI3K activation has been detected frequently in a multitude of cancers, including osteosarcoma. This chapter aims to characterize PTEN and the PI3K/Akt pathway in osteosarcoma, their effects on primary bone tumor behavior, and potential therapeutic targets