EGR1 and pituitary tumor: The regulation of the cell growth and proliferation by dopamine has been also confirmed in pituitary tumours where the activation of D2 receptor, especially D2S, leads to the activation of the MAPK pathway, c-Jun N-terminal kinase and early growth response protein 1 and the induction of apoptosis, consequently leading to the suppression of cell growth and proliferation in rodent lactotroph and somatotroph cell lines as well as in primary cultures of human non-functioning pituitary tumours [51, 55–57].