RESUMO
AIM: To evaluate the relationship between coexpression of EGFR and ERK2 on the level of protein and mRNA and activation of ERK2 in lung squamous cell carcinomas (SCC). METHODS: Twenty cases of lung squamous cell carcinomas and their paired normal lung tissues were studied. The expression of mRNA and protein of EGFR and ERK2 was measured by reverse transcription PCR (RT-PCR) and Western blotting, respectively. The activity of ERK2 was detected by immunoprecipitation and kinase reaction. RESULTS: The results showed that the expression of EGFR mRNA and protein in paired normal lung tissues was hardly detected by RT-PCR and Western blotting, respectively, but in 20 cases of lung SCCs their expression was upregulated significantly. Compared with normal lung tissues, the expression of ERK2 mRNA and protein in lung cancer tissues was also upregulated significantly, the latter increased about 3-5-fold, and the activity of ERK2 in lung SCCs was also markedly activated. CONCLUSIONS: These data highlight that the overexpression of ERK2 and EGFR protein occurs simultaneously in lung SCCs, which mainly results from the increasing level of gene transcription, the increased activity of ERK2 in lung cancer tissues perhaps attributes to the upregulation of coexpression of EGFR and ERK2. [