STAT3 and central nervous system neoplasm: While increased STAT3 phosphorylation was implicated in the mechanism of cell proliferation in CNS neoplasms [8,9,10,11,12,13], it is possible that decreased STAT3 phosphorylation, which was observed following exposure of astrocytes to ammonia, may have contributed to the impaired astrocyte proliferation following ammonia exposure, likely as a consequence of the increased senescence-associated genes expression levels [44].