MAPK3 and anaplastic large cell lymphoma: Moreover, since IL-2 is able to stimulate cells and augment the ERK1/2 kinase pathway, the presence of exogenous IL-2, not surprisingly, enhanced ALCL survival by overcoming the inhibitory effect of U0126, a specific inhibitor to the upstream kinase of ERK1/2 MEK1/2 (51, 54, 55).