FLT4 and neoplasm: Another important function of C/EBP transcription factors is to regulate gene expression, such as VEGFR3 in lymphatic endothelial cells [21], platelet-derived growth factor receptor in vascular smooth muscle cells [7, 14, 32], insulin-like growth factor-I in osteoblast cells [4, 11], and CXCR4 in tumor cells [1].