STAT3 and cancer: Up to date, major pathways and mediators contributing to inflammation and inflammation-associated processes in chronic diseases, especially in cancer, are known, whereat NF-κB, mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription (STAT)3, mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) and phosphoinositide 3-kinase/serine-threonine protein kinase B (PI3K/Akt) signaling (Figure 1) play an important role among some others and will be described in more detail in the following sections.