ATF4 and neoplasm: These results indicated that targeted therapy altered transcription factors.120 According to a recent study by Yang et al.,121 activating transcription factor 4 (ATF4) stress signaling led to rapid tumor evasion within a few days after the initiation of mitogen-activated protein kinase (MAPK) pathway inhibition, and was accompanied by elevated levels of microphthalmia-associated transcription factor (MITF).