MAPK1 and cancer: The ERK cascade currentlyrepresents the main targeted cascade (next to the angiogenic vascularendothelial growth factor/receptor (VEGF/R) system) by second-generation lowmolecular weight (LMW) kinase inhibitors (e.g., gefitinib, erlotinib) andmonoclonal (humanized) mAbs directed against members of the EGFR family (e.g.,herceptin), which are in clinical use against cancer (as reviewed in [25, 27, 28]).