To gain initial clues, we compared cellular MAP4K4 levels to the activation status of MAPK/ERK1/2, MEK1/2, MAKP/JNK1/2, MAPK/p38 as well as the serine/threonine protein kinase AKT in lung adenocarcinoma cell lines, evaluated by immunoblotting using specific antibodies against phosphorylated ERK, MEK, JNK, p38, or AKT. Here, MARK2 is linked to lung adenocarcinoma.