MAPK3 and non-small cell lung carcinoma: Therefore, we analysed the expression of phosphorylated (activated) ERK1/2 by immunohistochemistry with a phosphospecific antibody in a nonselected patient population with histologically proven NSCLC, and made correlations of the expression of this kinase with different clinical parameters and with survival, in an attempt to understand the role of activated ERK1/2 in these patients.