MAPK1 and cancer: Our group has previously reported that the radiosensitivity of cancer cells increases and that tumour growth is severely compromised following MEK/ERK inhibition after IR in cell systems from RAS mutant tumour cell lines and non-RAS mutant cell lines, the embryonal rhabdomyosarcoma, prostate-derived cancer cells and gynaecological-derived cell lines [107,111,112], while other groups have reported similar findings in different systems [126,139].