EGFR and lung cancer: Considering that the EGFR signal pathway was not only associated with angiogenesis [14], activating cell proliferation and epidermal mesenchymal transition in lung cancer cells [15], but also was related to bone matrix cell proliferation and differentiation [16], and that bone was a common site of distant involvement in NSCLC, we investigated bone metastasis and SREs among patients with known EGFR status.