MPL and cancer: Aberrant c-MPL signaling activates multiple oncogenic pathways, including Janus kinase/signal transducer and activator of transcription, phosphatidylinositol 3-kinase/protein kinase B, and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK), promoting tumor cell proliferation, survival, metastasis, and maintenance of cancer stem-like populations.