BMP4 and lung cancer: ZEB1, a transcription suppressor of miR-200, enhanced Bmp4 expression in a low metastatic lung cancer cell line (393P), but miR-200 suppressed Bmp4 expression in 344SQ (Fig. 1c) and 531LN2 (Additional file 1: Figure S4), which was confirmed by Western blotting (Fig. 1d).