In addition, expression of p-p38, CXCR1 and mesenchymal fibronectin were markedly reduced in A549 erlotinib-resistant tumor cells pre-treated with the p38 kinase inhibitor (Figure 4C), suggesting that blockade of p38 could alleviate mesenchymal features that, in turn, may contribute to tumor resistance. Here, CXCR1 is linked to neoplasm.