Moreover, it was reported that NSCLC cells with EGFR mutations manifest activation of the PI3K (phosphatidylinositol 3-kinase)-AKT and MEK-ERK (extracellular signal-regulated kinase) signaling pathways under the control of EGFR, and exposure of such cells to EGFR-TKIs blocks signaling by both pathways and induces apoptosis 13. To evaluate whether live vs. apoptotic CTC changes under treatment may be used as predictor of tumor response, M30-positive CTC will be quantified as previously 8.