NOX4 and non-small cell lung carcinoma: These results indicate that dysfunction of either Akt or NOX4 contributes NSCLC cell aggressiveness, and more importantly, the reciprocal activation between NOX4 and PI3K/Akt pathway may represent a positive regulatory loop that mutually reinforces the NOX4 expression and PI3K/Akt activity, further augmenting NSCLC cell aggressiveness.