KRAS and plexiform neurofibroma: Blockade of MAPK pathway signaling in BRAF-mutated melanoma or NF-1-mutant plexiform neurofibromas robustly induces cell death, whereas inhibition of MEK in KRAS-mutant pancreas cancer, including in KRASG12R-mutant preclinical models, is inducing p27-dependent cell cycle arrest without inducing apoptosis [21].