Conclusion
This study provides evidence that activated ERK1/2 and/or the combined activation of HER2 and ERK1/2 are good indicators of poor prognosis in NSCLC patients, not only in unselected patients but also in early stage disease.
Methods
Immunohistochemistry was performed to determine expression and activation of HER2 and ERK1/2 (detected by phosphorylation of Y1248 and T202/Y204, respectively) using Tissue Micro Arrays (TMA) containing matched normal and neoplastic tissues from 132 NSCLC patients. Survival analysis was carried out using the Kaplan-Meier method. Univariate and multivariate analysis were used to evaluate the prognostic value of pERK1/2, pHER2 and a combination thereof with clinical-pathological parameters such as age, lymph node status (N), size (T), stage (TNM) and grade.
Results
We found that HER2 was overexpressed in 33/120 (27%) and activated in 41/114 (36%) cases; ERK1/2 was activated in 44/102 (43%) cases. A direct association was found between pERK1/2 and pHER2 (23/41; p=0.038). In addition, patients positive for pERK1/2 and for both pHER2 and pERK1/2 showed significantly worse overall survival (OS) and disease-free survival (DFS) compared with negative patients. Univariate and multivariate analysis of patients' survival revealed that positivity for pHER2-pERK1/2 and for pERK1/2 alone were independent prognostic factors of poor survival in NSCLC patients. In particular, this association was significantly important for DFS in stage I+II patients.