EGFR and lung adenocarcinoma: A previous study[31] indicated that significant and specific down-regulation of EGFR expression by vector-based short hairpin RNA (shRNA) can inhibit human lung adenocarcinoma cell (A549 and SPC-A1) growth, induce cell apoptosis, and subsequently increase sensitivity to cisplatin, doxorubicin, and paclitaxel by about 4- to 7-fold in these two HLAC cell lines, respectively.