EGR1 and small cell lung carcinoma: Through a genome-wide transcriptomic analysis of the organ-preferential metastasis of human SCLC cells in mice, we found that EGR4, a member of a family of four related zinc-finger Cys2-His2 type proteins (EGR1 to EGR4), is significantly upregulated in bone metastatic tumors compared with other organs i.e., the lung, kidney and liver [7].