AHR and neoplasm: Moreover, in vitro studies succeeded in demonstrating correlations between pollutants and stimulation of pituitary cells: benzene and phthalates increased cell proliferation via a deregulation of aryl hydrocarbon receptor (AHR) and AHR-interacting protein (AIP) [20], a tumor suppressor pathway that seems to be involved with other xenobiotics, such as polycyclic aromatic hydrocarbons and PCBs [21].