The present study was designed to study the imatinib's targets (c-kit, VEGF, and PDGFR-α/β) expression in pituitary adenoma subtypes and elucidate the effects of imatinib on cultured human somatotropinoma cells and the rat somato-mammotroph GH3 cell-line and explore the plausible mechanism of action. The gene discussed is KIT; the disease is pituitary gland adenoma.