MAPK1 and cancer: This finding is consistent with miR-494 upregulation by ERK activation in non-malignant 293A cells.26 These observations highlight the increasing consensus that the physiologic relevance of each microRNA is highly contextual and cell type-dependent, and it critically demonstrates the complexity of miR transcription in various cancer types, for example, miR 494 may decrease in non-small cell lung cancer cells with ERK inactivation while enhancing TRAIL resistance.