Cell treatment with the specific MAPK inhibitors—PD98059, SP600125, or SB201190—that selectively block MEK1, the upstream kinase of ERK1/2, JNK, and p38 kinase activity, respectively, led to variable reductions in CF-induced levels of IL-6 in cell culture media (Figure 7). This evidence concerns the gene MAP2K1 and cystic fibrosis.