MAPK1 and cancer: Since our data showed that NVs and MVs from grapefruit reduced cycling and viability of cancer cells, we sought to assess their effects on the regulation of key molecular cascades involved in cancer cell survival, proliferation and aggressiveness, such as the phosphatidylinositol 3-kinase (PI3K)/AKT pathway and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway.