MAPK14 and non-small cell lung carcinoma: To determine which isoforms may play a role in regulation of stemness of NSCLC cells, we employed a 2-fold strategy, by either stably expressing wild type or constitutively active mutant of each p38 isoform in A549 and H460 cells, or by knocking down each p38 isoform using isoform-specific shRNA in H460 and H1299 cells [25, 26], followed by measurement of the expression levels of the stemness markers, the percentage of side population and the ability of the cells to form spheres.