STAT3 and cancer: Activation of the major hypoxicfactors (HIF-1) supports the creation of a cancer-promoting microenvironment.Hypoxia mainly affects solid tumors; however, pancreatic cancer differsfrom most solid tumors in its high stromal content, and thereforeit is characterized by a particular hypoxia and is able to survivein a changed microenvironment thanks to the mechanisms of interactionbetween pancreatic cancer cells and stromal cells and the activationof many signaling pathways, such as AKT, STAT3, and ERK.41