CD44 and lung cancer: Phosphoproteomic analysis of native (NCI-H520) and induced-resistant (H1581-9R and H1581-11R) lung-cancer cells compared with sensitive (NCI-H1581) and mutated AKT cell lines (mutant-AKT) revealed significant overphosphorylation of CD44 protein (by a factor of 30–50) at the site of serine-706 and PAK1 protein at site of serine-174 (Fig. 4h).