SRC and cancer: The hypoxic microenvironments are also associated with alterations in signaling proteins including Src, STAT3, phosphoinositide 3-kinase (PI3K)/Akt, extracellular signal-regulated kinase (Erk, also known as mitogen-activated protein kinase), and glycogen synthase kinase 3β (GSK3β), which are generally considered to be prosurvival (anti-apoptotic) and are commonly activated in cancer.